Both of these players headed into their encounter at the O2 Arena in London knowing that defeat would all but end their chances of reaching the semi-finals of the ATP World Tour Finals.
The history books made Juan Martin Del Potro the favourite, having won all three meetings between the two.
As it was, the Argentine ended up cruising to a two-set victory tonight over Janko Tipsarevic.
Below is our minute-by-minute updates of how the match unfolded.
Evening all. This may not be the most mouth watering of matches on paper, but it's straight knockout tennis which should hopefully bring out the best in both players.
No disrespect to Tipsarevic, but Del Potro is the bigger name of the two. The Argentine is a Grand Slam winner thanks to his success over Roger Federer at the US Open in 2009. From the the viewpoint of the neutrals, I think Del Potro would be the preferred winner.
He didn't start the competition too well though thanks to a three-set loss against David Ferrer on Tuesday night.
There was also a defeat for Tipsy during the opening round of matches. In truth, he was comfortably beaten by Roger Federer. However, he would have gone into that match knowing that his best chances of a victory would come against tonight's opponent and Ferrer, rather than R-Fed.
The history books would tell you that another defeat is heading Tipsy's way tonight though. In three meetings with JMDP, he's yet to win.
They first met in Miami back in 2009, where Del Potro claimed a 6-4 6-1 win. Then in 2011 at Delray Beach the Argentine come through 6-4 6-4.
Tipsy finally won a set against Del Potro in a Davis Cup clash in September of last year. However, it wasn't enough to prevent him from slumping 5-7 6-3 6-4.
We've just seen shots of Sergio Aguero at the O2, who will be supporting his fellow countryman Del Potro. He knows a lot of footballers! A couple of years ago he had Carlos Tevez in his corner. Does this mean that Del Potro is a Manchester City fan?!
"It's a very important match. We both know that if we lose there's not much chance to qualify. He's very good in the attack and serve. I'm going to try to be the more aggressive player," Tipsarevic tells Sky Sports News.
Del Potro adds: "It's going to be a tough match. I believe in myself and my ability to come through."
Here comes the players. Tipsarevic will be introduced to the crowd first.
Well, well. Del Potro wins the toss but decides to receive the serve. That's a strange decision in my opinion. He's a big server and you'd expect him to want to get off to a good start. Perhaps he fancies an early break.
We will be underway shortly. The two players are just going through a few service routines. By the way, Tipsarevic has broken two rackets already! Hope he's got plenty with him!
Tipsarevic gets us off and running at the O2 Arena...
Oh dear! Del Potro has three break points...
ACE! That's one saved by Tipsy in the best possible manner.
BREAK! But it's only a slight restbite for Tipsy as an unforced error gives JMDP an early break. Tipsy really didn't look comfortable there. We know he hasn't been well. Let's just hope he can continue and make a game of this.
Break point to Tipsarevic as Del Potro goes long...
ACE! Consider that well and truly saved by Del Potro! Deuce.
Tipsy goes wide with a shot he really should have made and Del Potro has an important hold. It's a missed opportunity for the Serbian.
Tipsarevic goes into the net and again he faces a break point...
BREAK! This could be over very quickly. Tipsarevic does not look to be at the races today. He goes long and 'Del Boy' is three games in front.
This is far too easy for Del Potro at the moment. He serves out to love. What's worse for Tipsy, he's broken a string on yet another racket. That's three already!
Three break points for Del Potro...
That's better! What a great forehand stroke across the court from Tipsy. He still has two break points to save though...
And Del Potro finds the net with the second. One more left...
That's fantastic from Tipsy. Another forehand winner brings up deuce. If he can escape here, it will do wonders for his confidence.
Slow reactions from Tipsy brings up another break point for Del Potro...
BREAK! And Del Potro doesn't let him off a fourth time. It's a little painful to watch at the moment if truth be told. Del Potro will now serve for the set.
Two set points for Del Potro...
ACE! SET! Well this is all too easy for Del Potro. Fair enough he's hitting his targets and playing some good shots, but Tipsy is not putting up much of a fight. The way it's going, I'd be surprised to see Tipsy finish this match. He doesn't look to be himself.
Once again Del Potro has a break point...
But Del Potro spurns the chance by firing into the net. Deuce.
Well that was hard work but eventually Tipsy holds! I don't think there has been a bigger cheer at the O2 all week. Let's hope that inspires him to make a game of this now.
Would you believe it? Following a smash, Tipsarevic has broken another racket. That's four! Madness.
A solid hold for Del Potro. Now, what dramas await us during Tipsy's service game?
None whatsoever is the answer to that question! It's a love service game would you believe. And to add to that, he's also had two of his broken rackets mended. Things are looking up!
It's a nice easy hold for Del Potro. Tipsy is yet to make any inroads on his opponent's serve. Still, at least he is competitive now.
Break point Del Potro. We've been here before...
BREAK! That could well be curtains as far as Tipsarevic's chances are concerned. He hits long and Del Potro has yet another break. That's got to hurt.
A speedy hold for Del Potro, who edges closer to the victory. Tipsy must hold now to stay in contention.
Yet another break point for Del Potro...
But Tipsy saves it with a powerful forehand stroke. That gets a big cheer from the crowd.
Great tennis from Tipsy pulls him through. As a result, Del Potro still just has a one-break lead. He will now serve in an attempt to keep that in place.
Yet another comfortable hold for Del Potro - he's had a night off where his serve is concerned basically. Tipsy now serving to stay in the match.
Fair play to Tipsarevic, he's making Del Potro serve for the match. If previous service games are anything to go by, it shouldn't be much problem for the Argentine.
A stunning backhand shot down the line brings up two match points for Del Potro...
GAME, SET AND THE MATCH JUAN MARTIN DEL POTRO
It only took one hour and 16 minutes for Del Potro to claim a vital win there. He now has a fighting chance of reaching the semi-finals, although he'll probably have to beat Roger Federer on Saturday. It will be a surprise if we see Tipsarevic again in this competition. He looks to be really struggling with the after affects of his recent virus.
"I'm trying to play my best tennis. It's not easy to win 6-0 because he is a very good player. I will try to beat Federer now," Del Potro tells Sky Sports News during his post-match interview on the court.
That's just about all we have time for this evening. We'll be back tomorrow though for Tomas Berdych vs. Novak Djokovic in the afternoon, before Andy Murray comes up against Jo-Wilfried Tsonga. Coverage will start at around 1.15pm. See you then.
