Rafael Nadal produced a stunning comeback to beat Daniil Medvedev on Wednesday at the ATP Tour Finals, saving a match point on his way to a 6-7 (3), 6-3, 7-6 (4) success.

After the players shared the first two sets, Nadal found himself 4-0 down and then saved a match point when trailing 5-1 in the decider. However, he produced a miraculous recovery to level the set up at 5-5 and then win an epic in the tiebreak.

Later in the day, Stefanos Tsitsipas booked his place in the semi-finals of the tournament with an emphatic 6-3, 6-2 win over Alexander Zverev.

Here are the results so far from Wednesday's play at the O2 Arena in London, as well as the schedule for Thursday's action.

ATP Tour Finals 

Wednesday Results

(1) Rafael Nadal bt. (4) Daniil Medvedev: 6-7 (3), 6-3, 7-6 (4)

(6) Stefanos Tsitsipas bt. (7) Alexander Zverev: 6-3, 6-2

Thursday Matches

(5) Dominic Thiem vs. (8) Matteo Berrettini

(2) Novak Djokovic vs. (3) Roger Federer

Wednesday Recap

This is the moment Nadal got the job done:

Nadal was a long way short of his best against Zverev and would have been intent on responding with a better performance on Wednesday in a repeat of this year's U.S. Open final.

Medvedev kept Nadal at arm's length in the opening stanza with some excellent serving. While the Spaniard didn't earn a break point in the first set, he was able to get to a tiebreak.

As he had been in the early stages of the match, Medvedev was the stronger player in the breaker and moved in front. Some of the angles the Russia was finding were puzzling Nadal:

Matthew Willis noted a recent abdominal injury appeared to be hindering the 33-year-old:

The top seed did fight back, as Medvedev lost his edge on serve in the second set, allowing Nadal to break and negotiate the majority of the set. 

After winning it 6-3, many would have anticipated the Spaniard to push on. However, it was Medvedev who found extra reserves and surged to a double-break lead.

Nadal avoided the ignominy of a bagel in the decider by getting on board at 4-1, and he ramped up the pressure on Medvedev after he broke back, moving to within a game of Medvedev at 5-4.

The tension was clearly inhibiting the Russian at this stage, and when Nadal broke again to square the third set at 5-5, the momentum had completely swung. George Bellshaw of Metro paid tribute to the legendary player's fighting spirit:

At this juncture, Medvedev did well to push the match into a tiebreak, thus giving himself some time to regroup at the changeover.

In the tiebreak, both men reproduced the standard of serving of the first set. However, when Nadal made it 6-4 and had his first match point, Medvedev missed a backhand and gave the Spaniard one of his most memorable wins of the year.

Tsitsipas and Zverev had the unenviable task of following that classic. It was the latter who settled the better of the two and took advantage.

The Greek was much the stronger player, showing off his thumping ground strokes and outmuscling Zverev with his hitting at times. Per Tumaini Carayol, Tsitsipas was also getting the better of his opponent at the net:

As the sixth seed wrapped up the opening set, Jose Morgado of Record commented on his strong run of form:

Zverev was unable to alter the course of the match in the second set, with his opponent simply too good in general play.

Per Ben Rothenberg of the New York Times, as the contest ebbed away from Zverev, his focus appeared to shift:

Another early break put Tsitsipas in complete control of the contest, before his second was consolidated at 5-1. Eventually, he clinched the set 6-2 as well as the match; on this evidence, the 21-year-old is someone to take seriously in the knockout stages.