Just a few hours after a comeback victory over Stefanos Tsitsipas kept his hopes of reaching the semifinals of the Nitto ATP Finals for the first time since 2015 alive, Rafael Nadal suffered a reversal of fortunes when defending champion Alexander Zverev defeated Daniil Medvedev in straight sets, eliminating Nadal from the season-ending championships.
Nadal had lost his opening round-robin match to Zverev in straight sets and when Zverev defeated Medvedev 6-4, 7-6(4) in Friday’s final round-robin match, it meant that three of the four players in Group Andre Agassi – Nadal, Tsitsipas and Zverev – all had won two matches and lost one. 
Tsitsipas finished top of the group after going 5-2 in sets and will consequently face Roger Federer, who finished second in Group Bjorn Borg, in Saturday’s first semifinal at 2pm GMT.
Nadal and Zverev both had two wins and one defeat, but Zverev had won the match between the two (and also had a better record in sets won and lost – 4-2 to Nadal’s 4-4) and consequently progressed to the semifinals for the second straight year.
Zverev will face Dominic Thiem, who impressed with victories over Federer and Novak Djokovic in Group Bjorn Borg, in Saturday’s second semifinal at 8pm GMT.
The defeat for Medvedev caps off a poor debut at the season-ending championships for the Russian, who climbed to world no. 4 after a sensational mid-season run of form saw him reach six straight finals, including winning Masters 1000 Series titles in Cincinnati and Shanghai and finishing runner-up to Nadal at the US Open in an electrifying five-set final. It’s a shame that the Russian finishes his ATP season on a four-match losing streak, having gone out of the Paris Masters early to Jeremy Chardy and gone 0-3 on his maiden appearance at the O2 Arena.
Zverev did lead the head-to-head 4-1 coming in, however, with Medvedev’s sole victory coming in the last encounter between the two in the Shanghai Masters final. Asked what Zverev did differently this time to change the result, Medvedev quipped: ‘He chose a different court probably 20 times faster.’
Medvedev added: ‘So I don’t think there was another tournament where I was so bad on return during the whole year. That’s where the result came from. … He didn’t have that many chances on return, either. Funny, tennis.’
Medvedev and Nadal are both due to play next week at the inaugural Davis Cup Finals in Madrid, so their seasons are not quite over yet.
Zverev has endured a difficult season in the wake of last year’s sensational ATP Finals victory, but returning to the scene of his biggest career achievement seems to have unlocked some more proactive, free-swinging tennis than we have seen from him for much of this year, and in a close encounter with Medvedev he was the sharper and more focused player (perhaps unsurprising given that Medvedev had no chance of reaching the semifinals).
The German seized an early break for 2-0 and although Medvedev dug out of a 0-30 hole to hold at 1-3 and keep the deficit to one break, the Russian never really had an opportunity to exert much pressure on Zverev’s serve until Zverev served for the set, and even then the world no. 7 climbed out of a 0-30 hole to wrap up a one-set lead.
The second set was characterized by efficient holds of serve for both men, particularly Medvedev, who won his first 14 points of the set on serve. The world no. 4 did create a tense 30-30 situation on Zverev’s serve at 2-3, having done well to force a volley error from Zverev and then profited from a double fault, but Zverev pulled out a big delivery under pressure to get to game point and went on to hold, and the run of one-sided service games resumed.