Good afternoon! It's half an hour until South Africa's final game in the pool stage of the Rugby World Cup, with the two-time champions needing a win over the USA to make sure of their place in the last eight. Let's start with a reminder of the team news.

SOUTH AFRICA STARTING XV: Le Roux, Habana, Kriel, De Allende, Mvovo, Pollard, Du Preez, Mtawarira, Du Plessis, Malherbe, Etzebeth, De Jager, Louw, Burger, Vermeulen

USA STARTING XV: Scully, Thompson, Niua, A Suniula, Test, S Suniula, Kruger, Kilifi, Thiel, Baumann, Stanfill, Trouville, Barrett, Quill, Manoa

South Africa are taking no chances with their team selection, making just two changes to the side that beat Scotland last weekend. JP Pietersen and Jannie du Plessis are both carrying minor injuries, so they're rested, with Lwazi Mvovo and Frans Malherbe coming in.

The USA have had 10 days rest since letting a lead slip against Scotland in their second match of the tournament. With another fixture to come just four days after this match though, there are 12 changes for Mike Tolkin's side, with only captain Manu Samoa, Phil Thiel and Blaine Scully retaining their places in the lineup ahead of Sunday's match against Japan in Gloucester. The Americans are still looking for their first win of the tournament.

Ahead of this match, South Africa head coach Heyneke Meyer told reporters: "There are so many examples of comebacks throughout the world of things that people said could never happen. They said the mile would never be run in under four minutes, and now everybody's running under four minutes. I am a very positive person. IO believe anything is possible, and I have been in situations where I've lost every single game, come back and won trophies. But we don't look past this game. I mean it."

Meanwhile, the USA's Mike Tolkin said at his pre-match press conference: "It comes to a point in this tournament with a four-day rest where you have to use the whole squad. Every team that has been in this situation has had to do the same thing. The morale is good, the work ethic is very good. We are just disappointed we didn't get those wins. We knew each World Cup game is a challenge, but we also felt that we could win."

South Africa sit at the top of the Pool B table ahead of this match. A victory would ensure that they progress to the last eight, while a bonus point would ensure that they finish at the top of the table, therefore avoiding the winner of Pool A in the last eight. Japan and Scotland are also fighting for a spot in the last eight. Meanwhile, the USA have an outside chance of finishing third in the pool and securing qualification for the 2019 tournament in Japan, but they'll need bonus point wins from their remaining two fixtures.

Both sides have been heavily supported throughout this tournament so far, and it looks like today will be no exception:

This is the first of two fixtures taking place today, with Georgia and Namibia going head to head later. If you've missed any of the action from our Rugby World Cup coverage, you can catch up on the tournament page.

The players make their way out ready for kickoff. As is always the case, the anthems for both teams will be played before the start of the match. Given the support both sides have received, it should be a pretty lively anthem singing display by the crowd.

Some of the American fans really went for it during the Star Spangled Banner, but it sounds like South Africa just edged it in terms of numbers in the Olympic Stadium this afternoon. Kickoff should just be a few moments away now.

KICKOFF! The USA get the action underway.

The USA have made a bright start with Shalom Suniula and Louis Stanfill moving the ball into South Africa territory early on, before they force the first penalty of the match, with Schalk Burger hitting the latter around the net, but he avoid a sin-binning.

MISSED PENALTY! There's a bit of confusion as the USA initially elect to kick for a lineout, but the referee realises that he was in the wrong position. With a kinder angle, Folau Niua decides he'll have a go at the posts instead, but it falls just short.

The USA have possession again, but a knock on gives South Africa the first scrum of the match. Du Preez is waiting for it at the back, but there's a penalty, so the Springboks kick it away for a lineout, which will be their first possession in USA territory.

Handre Pollard gets the ball and kicks it forward for Mvovo, but the Americans soon force a turnovers, but Thompson dragging the winger down, but a wayward pass ends up going into touch to give the ball back to South Africa.

It doesn't take South Africa long to have an impact as the ball comes loose from the lineout, but Schalk Burger manages to scoop it up and pass it inside for Damian de Allende, who sprints over between the posts for his first international try.

After Pollard kicks the additional two points, the USA finally get possession back and try to build possession, as they did so well in the opening five or six minutes of the match. The Americans force a penalty to allow them to kick it out of their own territory, before Kruger and Trouville get touches in the middle, but the Springboks have a well-organised line allowing them to stop the charge.

MISSED PENALTY! South African-born Niku Kruger takes over the kicking duties for the USA after Eben Etzebeth is penalised for not rolling away in the maul. The scrum-half can't quite curl it around though, as he watches his effort strike the post.

The Springboks win another lineout, which Lood de Jager takes in the air before Du Plessis leads the maul, but Phil Thiel concedes a scrum. Despite the USA's impressive possession so far, the two-time champions look by far the more dangerous.

There's a potential injury problem for South Africa as Schalk Burger hits the deck following a lineout, and he seems to be in quite some pain. Looking at the replays, be appears to accidentally collide with one of the Americans, taking a knee to the ribs, which seems to have winded him.

Bryan Habana has been quiet in the opening 20 minutes of the match, but he gets the ball from a kick forward before quickly passing to Willie le Roux on his right. The winger is involved again moments later as he tries to beat Blaine Scully to a high ball. The South African catches the American full-back though, knocking him mid air to leave him landing on his shoulders. After looking at replays of the challenge, the officials are happy they were both going to the ball though, so Habana avoids any punishment, aside from conceding a scrum.

Habana took blow to the head during his collision with Scully, so he's going off for a head injury assessment, while Scully is also going off for checks. Jan Serfontein and Chris Wyles take their places respectively.

The USA have the ball near the half way line, but they're turned over again, with Burger winning the ball back for the Springboks before Pollard breaks free, sprinting towards the corner, but the fly-half is tackled just short.

NO TRY! South Africa keep the ball alive, with De Allande passing the ball out wide for Jesse Kriel. The centre tries to power over, but Kruger does enough to ensure that he comes down inches short, before Zach Test prevents him stretching it across the line. It's a brilliant defensive effort by the duo.

South Africa are still knocking on the door as they press for a second try, with Etzebeth trying to use him size to smash his way through for South Africa, but he 6'8" lock can't keep hold of the ball. Meanwhile, Habana and Scully, who both went off for head injury assessment, have both been cleared to return.

The USA are having a few problems with their scrum, with it collapsing twice in quick succession. The referee gives them one final warning before awarding a penalty try.

After seeing plenty of the ball in the first 10 minutes, the USA have found themselves pinned back in their own half for much of the last 15 minutes, and the South Africans have the ball again as they win a lineout, with De Jager winning it in the air. There's a worrying moment for the referee too as he gets a bit too close to the action while watching a maul, getting knocked by the ball. It's another blow for the USA, as he has to award South Africa a scrum.

Finally there's a break for the USA, as they win a penalty, setting Phil Thiel up for a lineout. Samu Manoa, who has really been very quiet in the first half hour, tries to gain some territory, but he's soon bundled to the ground.

USA can't sustain the pressure, allowing South Africa to make their way back into American territory. Le Roux makes a brilliant pass across the pitch to Mvovo, who is immediately tackled by Thompson before he can sprint to the corner.

The Springboks are pushing for a third try before half time, as the ball is passed out wide for De Jager, but Scully intercepts the pass and tries to break away down the sideline, but he's lacking support, allowing South Africa to halt the full-back's run.

So, at half time the Springboks have one foot in the quarter-finals thanks to a penalty try and a score from Damian de Allende, but the USA have had a few promising spells, particularly in the last couple of minutes following Scully's interception.

In the first 40 minutes, South Africa just edged the territory with 40%, but is was the USA who had slightly more possession with 52%. South Africa have made 196 attacking metres, 53 more than their opponents, but Blaine Scully has been the most active player going forward.

Defending is where the USA have come unstuck, missing 16 tackles, while South Africa have missed just two of 64. The Springboks have also forced six turnovers, while the USA have just one.

Bryan Habana's collision with Blaine Scully has been subject to some debate, particularly on social media. In previous years, the South African's hit on the USA full-back would have resulted in a red card, but changes to the rules in the last couple of years has resulted in the punishment for such a challenge being relaxed. However, there have been yellows given for similar collisions in this tournament, so the winger may have been a touch fortunate not to have a spell in the sin bin.

South Africa won't be counting this as a victory yet. Although they have what seems to be a comfortable lead at the interval, they will be aware that Canada let a 15-0 lead slip yesterday in their defeat to Romania, which is a record comeback in the Rugby World Cup.

The players are making their way back out ready for the start of the second half.

RESTART! Handre Pollard gets the action back underway.

Just a few minutes into the second half, South Africa have extended their leads thanks to the stunning pace of Bryan Habana, who scores his 62nd international try for the Springboks. Fourie du Preez chips the ball forward for the winger, who just stays onside long enough to legally take the ball before leaping over in the right corner.

So, South Africa need just one more try to secure a bonus point, but it's the Americans who are on the ball as Brett Thompson grabs a high ball, but the winger steps into touch, so South Africa have a lineout. If the USA want to avoid a heavy defeat, they really need to score next.

From the lineout, the Springboks are piling towards the try line again, with Etzebeth and Vermeulen both trying to squeeze their way over. The USA do enough to hold the duo up, but they've got a scrum to defend, having struggled with their front row in the first half.

Schalk Burger can't squeeze through for the try as South Africa drive towards the line from the scrum, but he does pass to Du Plessus, who has Etzebeth to help shove him across the line for the fourth South Africa try. Pollard can't add the conversion though, missing for the first time today.

Schalk Burger's day is done as he's heading off, with Willem Alberts coming off the bench, while Manu Samoa is also heading off for the USA.

Having been made to work hard for their points in the first half, South Africa are in cruise control now, with Francois Louw, who has played every minute of the tournament so far, getting the ball from a scrum and keeping it as the Springboks drive across the line, setting him up to ground it just to the right of the posts.

The USA's heads appear to be dropping as South Africa quickly get the ball back in America territory, but Damian de Allende can't keep hold of the ball, spilling it to give the USA a scrum.

Despite the USA having the scrum, it's the Springboks who get the ball back, with Jesse Kriel charging forward. He has Habana to his right, but is eyeing the line himself, knocking on as he's tackled by Danny Barrett.

USA lose possession from a lineout, with De Jager taking the ball in the air, passing to De Allende, who this time uses Habana, passing it inside to the winger, who is left with an easy run to the try line from five metres out for his second try of the match.

Habana's face lights up as he's left with yet another easy surge across the line to complete his second-half hat-trick. Vermeulen picks the ball up, with Habana waiting unmarked to his right, leaving the winger with one of the easiest tries he will ever score.

The USA win a penalty in South Africa territory, and elect to kick it for a lineout rather than going for the posts as they continue to look for their first points of the match. Shalom Suniula's kick to the corner is short though, allowing South Africa to keep the ball in play. Brits tries to run it through the middle, but is stopped by a high tackle from Maoakiola.

There's a wry smile from Habana as he chases down a kick forward from Le Roux, looking for his fourth try of the match, but it slips straight through his arms as he dives for the line.

Schalk Brits takes a lineout at the five-metre line, setting up Francois Louw for his second try of the match, as he benefits from the Springboks' drive again, which has been ruthless this evening. Morne Steyn's conversion goes wide though.

Schalk Brits has been really lively since coming off the replacements bench midway through the second half, and he's involved again as he weaves down the left before looking for Nyakane, but his run is halted.

It's becoming a real thrashing now as Jesse Kriel makes the most of a slip from Chris Baumann to run out to the corner, sliding across for South Africa's eighth try of the match. Once again Morne Steyn misses the conversion though. He's doing nothing to loosen Handre Pollard's grip on the number 10 shirt.

It's been just relentless from South Africa in the second half, with the Sprinboks forcing a scrum in their own territory, before Le Roux skips back into the USA's half. Page and Alberts keep the attack going. There's still plenty of time for South Africa to add to the scoreline again.

Brett Thompson manages to regain possession for the USA after a kick forward from South Africa, as he immediately comes under pressure from Serfontein, but the winger keeps calm and is unable to get the ball clear. South Africa will have another lineout though.

The USA are desperately trying to launch a late attack just for some consolation points, with Wyles getting the ball across to Quill, but Le Roux gets the ball back for South Africa. They work the ball across the pitch to Habana, but the winger is unable to keep hold of it.

Incidentally, had Habana managed to cross the line for his fourth then, he would have broken Jonah Lomu's record for most tries at the Rugby World Cup, having tied the New Zealander's total of 15 earlier in the second half.

The USA are keeping the ball alive as chants of "USA, USA USA" fill the Olympic Stadium. Kruger and Suniula work hard to keep it moving, before Taufetee breaks free looking for a try on his World Cup debut, but Le Roux is there to bring him down.

What a heart-breaking finish to the match for the USA. Just as they're stringing together a promising attack and look like they might get on the board in the final seconds of this match. Lwavi Mvovo intercepts a pass, kicking it forward for himself several times before leaping over in the corner.

Well that was brutal! South Africa have sent a real message to anyone who doubted them following the loss to Japan, absolutely crushing the USA at the Olympic Stadium to ensure that they progress to the quarter-finals as Pool B winners, where they will face the loser of Saturday's match between Australia and Wales.

Bryan Habana will be happy with his performance today, having scored three tries to match Jonah Lomu's Rugby World Cup try record. He's scored five at this tournament alone, and you have to fancy he'll break the New Zealander's record in the last eight.

So, that's all from this match, but join us again later to see if Georgia or Namibia can secure their first win of the tournament as they meet in Pool D. Until then, thanks for joining me this afternoon. Goodbye.