The Swiss number two led 5-2 in the opening set, but the world number three fought back to clinch a one-set lead in the tiebreak.
However, the world number eight came back in the second set, before swiftly wrapping up the decider.
Read how all the action unfolded below:
2.02pmGood afternoon. It's the final set of round robin fixtures for Group A at the ATP World Tour Finals today. A win for Stanislas Wawrinka would likely send the Swiss through to the last four, depending on this evening's result.
2.06pmThe players will be a few minutes later than expected, as the earlier doubles match took longer than predicted. This will be the 11th match between these two players, with the Spaniard having a 7-4 advantage. They've only met once before on an indoor court, with Ferrer winning in three sets.
2.10pmFerrer previously reached the final of this tournament in 2007, when the event was held in Shanghai. On that occasion, he lost in straight sets to Roger Federer.
2.13pmThis is the first time that Wawrinka, who is currently ranked eighth in the world, has qualified for the Finals. If he wins this afternoon, Tomas Berdych will have to get the better of world number one Rafael Nadal later today.
2.16pmThe players are making their way into the arena. Wawrinka heads out first, closely followed by Ferrer. It sounds like it's fairly neutral crowd in the O2 Arena this afternoon, with both players receiving a similar amount of cheers.
2.19pmFerrer comes into this tournament off the back of a lengthy campaign at the Paris Masters last week, where he reached the final for a second year in a row, before losing to Novak Djokovic. Wawrinka has had a much quieter schedule recently, having lost in the third rounds at Paris and in the Shanghai Masters, while exiting in the first round in Basel.
2.22pmThis will be the third match between Ferrer and Wawrinka this year. Both of their 2013 meetings have been on clay, and they've won one match each. The players are just coming to the end of their warm-ups, so we should be getting underway in the next couple of minutes.
2.25pmPREDICTION! Ferrer may have the higher ranking, but Wawrinka has looked in form this week, and with the prize of a place in the semi-finals on offer, I think the Swiss player will be victorious this afternoon. Ferrer should put up a good fight though, as he'll be keen to avoid losing all three matches in straight sets, so I'm going for Wawrinka in three sets. Play is just about to get underway, with Wawrinka serving first.
Ferrer *0-1 WawrinkaWawrinka makes a nervy start, faulting his first serve before losing out to a strong return from his opponent. However, he finds his accuracy and power to send a series of pacy serves past the Spaniard to wrap up the opening game of the match.
Ferrer 1-1* WawrinkaFerrer makes a comfortable start on serve, as Wawrinka makes a couple of errors on return, before Ferrer clinches the game with a backhand winner. Both players have looked pretty composed in their first service games, it looks like breaks are going to be hard to come by this afternoon.
Ferrer *1-2 WawrinkaWawrinka races to a 40-0 lead, but some solid play at the net from Ferrer gets him back into the game, before the world number eight wraps it up with his second ace of the game.
Ferrer 2-2* WawrinkaFerrer drops just the one point for another swift hold of serve, but he had to work harder for his points this time around, as Wawrinka manages to return the Ferrer serve well, but is undone by his opponents quick movement along the baseline.
Ferrer *2-3 WawrinkaThere's still no sign of a break for either player as Wawrinka cruises to another hold, clinching his third ace of the set along the way before Ferrer slices his backhand into the net.
Ferrer 2-4* WawrinkaBREAK! Wawrinka defends well from the back of the court, keeping his returns deep to prevent Ferrer from coming into the net, and it forces a mistake from the Spaniard to bring up the first break point of the match, but a hit off the net chord sees his forehand carried long to take the came to deuce. The Swiss gets another chance when the world number three drags his forehand wide, and he catches Ferrer out with a stunning cross-court backhand, which leaves the Spaniard stretching. He manages to hit the ball back, but it finishes well long.
Ferrer *2-5 WawrinkaWawrinka makes a quick start as he looks to consolidate the break, firing his fourth ace of the match past Ferrer. The Spaniard provides some resistance to keep himself in the game at 40-30, but another big serve from the seventh seed seals the game, leaving him just one short of winning the opening set.
Ferrer 3-5* WawrinkaFerrer looks to be in control, taking a 40-15 lead with some tidy serving, but Wawrinka fights back, hitting the ball hard from behind the baseline to take the game to deuce. However, the world number three manages to increase the tempo of his serve to force advantage before clinching the game. Wawrinka will now serve for the opening set.
Ferrer *4-5 WawrinkaBREAK BACK! Having focused one serving down the tee for much of this set, Wawrinka tries to deliver the ball out wide. At first, it looks to be helping Ferrer as he claims the opening couple of points, but the Swiss gets himself back into the game with another ace. However, he smashes his forehand into the net on the next point, giving Ferrer the chance to break back, and he gifts his opponent the game with the first double fault of the match from either player.
Ferrer 5-5* WawrinkaFerrer is rejuvenated following his success in the previous game. A good challenge gives him a 40-0 lead, but a couple of loose shots from the Spaniard let Wawrinka back into the game. However, Wawrinka mis-reads his opponent's serve at 40-30, tapping the ball into the net to allow Ferrer to level the set.
Ferrer *6-5 WawrinkaBREAK! Ferrer makes a good start as he tries to make in four games in a row, but Wawrinka fights back, sending some potent serves into the court to edge a 40-30 lead, but he tries to force a winner during a lengthy rally, allowing Ferrer to take the game to deuce. Ferrer claims advantage to get another break point, but the Swiss comes into the net to volley. Wawrinka goes on to save four break points during the game, but Ferrer eventually manages to force back-to-back errors from the world number eight to go a break up for the first time in this match, and he'll serve for the opening set next. Both players look drained by that game, which is not surprising, as it lasted for almost 14 minutes!
Ferrer 6-6 WawrinkaBREAK BACK! Wawrinka responds well to losing his serve, coming out aggressive to quickly get the break back to love, forcing this set into a tie break.
TIEBREAKFerrer 4-0* Wawrinka. Wawrinka is a little unlucky to strike the net chord, but Ferrer shows his full range of shots as well as impressive pace, coming into the net before rushing back to return a lob.
3.28pmWawrinka plays some good shots from the back of the court as he tries to keep himself in the tiebreak, but the ball keeps coming back, so he tries to add more power, but fires it long to give Ferrer the opening set.
3.29pmFerrer showed impressive resilience to get back into that set, having found himself 5-2 down at one point. Wawrinka has shown flashes of brilliance, but hasn't been consistent enough so far.
Ferrer 7-6 1-0* WawrinkaFerrer looks to be more determined than ever, as he smashes the ball into his opponent's side of the court, quickly wrapping up the opening game of the second set, as Wawrinka struggles to return the ball.
Ferrer 7-6 *1-1 WawrinkaWawrinka is really struggling to get any sort of momentum going. He misses all of his first serves as Ferrer finds himself 40-30 ahead, but then records an ace to bring up deuce. After saving a second break points with another ace, Wawrinka manages to get the better of the Spaniard in a rally, before slicing a backhand winner past Ferrer to hold serve.
Ferrer 7-6 1-2* WawrinkaBREAK! It's another close game, which Wawrinka manages to take to deuce to a superb backhand. A mistake by Ferrer gives the Swiss a chance to break, resulting in a series of angry shouts from the Spaniard. While trying to save the break point, he sends his forehand into the net to give the world number eight the game, before smashing his racquet on the court's surface. That probably won't have gone down well with the umpire!
Ferrer 7-6 *1-3 WawrinkaFor the first time since leading 5-2 in the opening set, Wawrinka seems to have some consistency to his game. He looks comfortable as he finds some strong serves before making shots from all around the court to quickly consolidate his break, allowing Ferrer just one point.
Ferrer 7-6 2-3* WawrinkaFerrer is back on form in this service game. Wawrinka tries to force more errors from the Spaniard, having frustrated him from the back of the court on serve last time around, but Ferrer is aware of his tactics this time around, and manages to wrap it up with some big serves to keep himself in contention in this set.
Ferrer 7-6 *2-4 WawrinkaWawrinka makes a slow start to the game, allowing Ferrer to grab a 30-15 lead, but his eighth ace of the match gets him back on terms, before some more solid backhand strokes wrap it up.
Ferrer 7-6 3-4* WawrinkaAfter his struggles earlier in the set, Ferrer is back on form on his own serve, comfortably holding off Wawrinka again, despite the Swiss pushing hard for a second break.
Ferrer 7-6 *3-5 WawrinkaWawrinka uses the full width of the court to stretch his opponent before serving another ace and clinching the game with an overhead lob close into the net. Wawrinka is looking good in this set, but was equally strong at the start of the first, so there's still time for Ferrer to get back into this.
Ferrer 7-6 4-5* WawrinkaWawrinka is still playing aggressively, clearly eager to win the set on Ferrer's serve so that he can serve first in the deciding set, but the Spaniard travels the lengthy of the baseline to make a stunning slices backhand to keep himself in the game, before clinching the game with the help of some powerful serving. Wawrinka will serve for the second set next.
4.13pmSET! David Ferrer 7-6 4-6 Stanislas Wawrinka
4.14pmThe players split the opening four points, but a serve into the body from Wawrinka gives him set point, which he converts when Ferrer forces his forehand wide.
Ferrer 7-6 4-6 0-1* WawrinkaBREAK! Wawrinka is initially deceived after Ferrer's forehand clips the net chord, but he reacts well to send a forehand winner back down the sideline. At 30-30, the third seed blasts a ground stroke well long to give Wawrinka a chance for an early break, which he takes when the Spaniard mis-hits his forehand again, sending the ball well wide.
Ferrer 7-6 4-6 *0-2 WawrinkaWawinka's first two serves of the deciding set are aces. Ferrer manages to take a point with a solid forehand winner from the back of the court, but the Swiss's serve is too good, as he finishes the game with another ace. The world number eight looks in complete control at the moment.
Ferrer 7-6 4-6 1-2* WawrinkaFerrer steps it up, quickly taking a 40-15 lead. While looking to wrap things up, Wawrinka makes the Spaniard work hard, slicing several backhands at his opponent. He changes direction, hitting into the open side of the court in a bid to force a winner, but he puts too much on the ball, and it goes wide.
Ferrer 7-6 4-6 *1-3 WawrinkaIt's another comfortable hold for the Swiss, who seals the game with yet another ace. Ferrer's recent busy schedule appears to be taking it's tole, as he's not moving around the court quite as quickly as he was earlier in the match.
Ferrer 7-6 4-6 1-4* WawrinkaBREAK! Wawrinka drags Ferrer out wide with a backhand, giving the Swiss a chance to come into the net and volley, but he doesn't give his shot enough lift, and it fails to clear the net. At 30-30, Wawrinka seems to be in control of a lengthy baseline exchange, but a hurried forehand catches the net, but Ferrer makes the same mistake on the next point to take the game to deuce. The Spaniard overhits his forehand to give the world number eight a chance to clinch his second break of the deciding set, and he takes it with a superb backhand, which causes Ferrer to lose his footing.
Ferrer 7-6 4-6 *1-5 WawrinkaFerrer hasn't given up yet, as he claims the opening couple of points, before chasing a lob from Wawrinka in a bid to bring up three break points, but he can't quite reach it in time. The Swiss manages to get back on level terms, before his next two serves go unreturned, leaving him just one game short of the match win.
4.44pmAfter a series of errors from Ferrer, Wawrinka has a match point.
4.45pmGAME, SET & MATCH! David Ferrer 7-6 4-6 1-6 Stanislas Wawrinka
4.46pmA double fault from the Spaniard leaves Ferrer in trouble, but he comes into the net to volley, which Wawrinka can't return. A backhand sliced into the net brings up a match point for Wawrinka, which he converts with a brilliant forehand return to give him his second win of the week.
4.48pmThe Swiss looked on shaky ground after the first set, having thrown away a 5-2 lead to lose in a tiebreak. He needs to hope that Rafael Nadal beats Tomas Berdych in the other group A match later today in order to seal his place in the last four in his first appearance at the Finals.
4.50pmThat's all from the ATP World Tour Finals for now, but join us again from 8pm, when world number one Rafael Nadal will be looking to finish the round robin with a 100% record as he faces Tomas Berdych. Until then, thanks for joining me this afternoon, goodbye