Hello, and welcome to Sports Mole's live coverage of the match at the ATP World Tour Finals between Novak Djokovic and Tomas Berdych.

It's the sixth and final day of group-stage competition and what better way to kick it off than with the world number one. Novak Djokovic has performed at an incredible level in his opening two matches, dropping just five games along the way, but he still needs a few games to make sure of his place in the last four. Surely a formality, right?

Standing in his way this afternoon is Tomas Berdych. The big-hitting Czech responded from an opening defeat to Stanislas Wawrinka to convincingly beat Marin Cilic on Wednesday which has given himself a chance of making the semi-finals. There's just the small matter of overcoming the defending champion, probably in straight sets too. Good luck, Tomas...

Just to give you an indication of the task in hand for Berdych today - Djokovic is nearing 30 successive wins indoors and has won 25 sets in a row, which is simply phenomenal. Djokovic has also won 16 of their 18 meetings on the ATP Tour, with a triumph on clay being Berdych's only win against the Serbian in the past four years.

The odds are obviously stacked against Berdych but at least he can come into this match with the feeling of having nothing to lose. Sure, he needs to beat Djokovic, but no-one, not even Tomas, is expecting to get past the world number one today. He needs a quick start though and a hold of serve in the opening game.

BREAK! Berdych starts with a poor second serve that Djokovic swats away. That's not what you want. Djokovic then gets Berdych on the run to force the error, and already, this is looking ominous. Another shot into the net from Berdych hands three break points to the world number one who takes it with a huge backhand return.

Djokovic eases into a 30-0 lead before Berdych connects with a first-serve return to get up and running. The crowd liked that. The Serbian then double faults - what is going on?! Minor blip, though. An ace down the middle gets him to game point before Berdych nets a forehand. Break of serve consolidated.

BREAK! Better from Berdych, who strides into the net to put away a volley, and he looks on course for 30-0 before Djokovic's displays his incredible powers of recovery for 15-15. Djokovic then goes on the offensive to give himself two opportunities of the double break but he squanders the first by miscuing a second-serve return. He takes the second, though, as a Berdych forehand clips the net and goes wide. You know, I think Djokovic wants this double bagel. He's got that look in his eyes...

Djokovic starts his second serve game with an ace register just 112mph before following that up with a quite ridiculous drop shot on the half volley. The world number one shows he is human when dumping a backhand into the net but he has the ball back on a string in moving Berdych around the court before converting the easiest of volleys. Another volley of similar difficulty gets the hold to 15.

A double fault from Berdych gets him off to the worst possible start but a smash and an ace get him to 30-30. Djokovic then proceeds to send a return wide and it's game point to Berdych! A solid return comes back at him but Djokovic eventually nets to concede the game. That will be a relief to the Czech.

What are the chances? Boris Becker has just caught the ball in the crowd. His man is enduring a bit of trouble on the court though now as Berdych powers his way to 15-30. That's as good as it gets, though, and three first serves are enough to take Djokovic to within one of the set.

Berdych is doing alright now. A baseline winner and smash into the corner are enough for 30-0 and although Djokovic halves the deficit, Berdych has two game points after an unforced error. He goes long on the first, but Djokovic nets once again to hand the Czech a second game.

SET! Djokovic's level has dropped from superhuman in the past couple of games but respective backhand and forehand winners take him to 30-0. He's unfortunate to see a Berdych lob catch the line but he's fortunate to survive a passing shot from the Czech that gives him to set points. The first is taken when a return from his opponent goes long and that's the set done and dusted in just over 30 minutes.

That set has guaranteed Djokovic in the last four and effectively setting up a semi-final showdown with Kei Nishikori. If he can come through this match, he will guarantee himself the number one position for the end of the year too.

BREAK! Berdych had a nightmare start to the first set but when he gets to 40-0, it looks like a completely different story for the second. However, a double fault contributes to Djokovic getting back to deuce and the world number one puts enough pressure on the Czech to seal the break. It's a long way back from here.

Berdych has an opening at 0-15 but he can't take advantage of a couple of second serves from his opponent and after Djokovic ghosts into the net to convert a volley, he has two game points. Berdych is having problems with the Djokovic second serve and he can't return another to concede the game.

BREAK! A sublime backhand pass from Djokovic - it probably feels routine to him - beats Berdych all ends up for 0-15 before a couple of errors from Berdych allow Djokovic to comfortably reach 15-40 and after a backhand down the line goes into the tramlines, the double break is sealed. Berdych has made 10 mistakes in the opening three games of this set. Blimey.

At 15-15, Berdych gets a foothold in a baseline exchange but he finds unreal resistance from Djokovic. The world number one follows that point up with a couple of meaty first serves for the hold to 15.

There's encouraging signs for Berdych after a sharp one-two off his serve, but Djokovic is relentless and a forehand down the line levels the score. The next two points are shared but Berdych finds himself break point down yet again when he dumps a backhand long of the baseline. Berdych survives though and avoid the bagel.

Berdych loosens the shackles with a blistering forehand return but Djokovic restores order with a routine one-two. Berdych continues to go for his shots but misses his mark twice in succession before an ace takes him a game away from sealing his world number one position in the world rankings for the start of next year.

No-one has taken more than three games off Djokovic in this tournament, but Berdych is well on his way when he blasts his way to 40-15. He wastes no time in bettering that mark when he chases down a drop shot before angling the ball into the corner.

MATCH! Djokovic's length of shot is frightening at times and it does for Berdych twice as the 27-year-old begins his march to victory. A cross-court forehand clips the line to earn him three match points, and after 68 minutes, a forehand into the corner secures himself not only the match but seals the number one spot.

That seemed so easy for Djokovic. He showed that he was human now and again, but on the whole, that was another commanding performance that left Berdych beaten as soon as he dropped his serve in the first game of the match.

The emotion that Djokovic displayed after the final point showed how much being world number one means to him, but that's only half of the job done in London. He now progresses onto a semi-final with Kei Nishikori on Saturday, who defeated him at the US Open earlier this year. Common sense would suggest that this game will take place tomorrow afternoon.

On that note, we will bring an end to Sports Mole's coverage of this match but that's not it for today. We have Stanislas Wawrinka against Marin Cilic coming up at around 8pm, GMT. Goodbye for now.