Novak Djokovic continued his ATP Finals winning streak with a win over Daniil Medvedev in Turin.
Djokovic had already secured the top spot in the red group but had to fight back to secure a 6-3 6-7 (5-7) 7-6 (7-2) victory in three hours 11 minutes.
Medvedev led 5-4 and served for the match in the decider before Djokovic recovered to lead the set to a tie-break.
“It’s a huge relief,” Djokovic told Amazon Prime Video.
“Daniil and I have had a few battles in the past and I knew that going into today’s game it would be his last game of the season, and he definitely won’t want to end the season with a loss.
“I started very well, I had my chances at the beginning of the second. He just played very well in those decisive moments. I didn’t feel very good physically in the third set to be honest, I had a lot struggled to physically stay there.
“I’m really proud that I was able to find that last drop of energy and focus needed to get back into the game.
“This match against one of my biggest rivals today was very important, even though I had already qualified and really wanted to win.”
Djokovic will face American Taylor Fritz in the semi-finals on Saturday, while Medvedev will exit after losing all three group matches.
Russian Andrey Rublev completes the last four men’s singles after beating Greek Stefanos Tsitsipas 3-6 6-3 6-2.
Rublev advances to the semi-finals as second in the red group and will face Norway’s Casper Ruud.
Meanwhile, Britain’s Neal Skupski advanced to the men’s doubles final alongside Dutch partner Wesley Koolhof after results elsewhere.
Green group winners Nikola Mektic and Mate Pavic maintained their winning streak to beat Nick Kyrgios and Thanasi Kokkinakis 7-6 (7-4) 7-6 (7-4).
The result meant Skupski and Koolhof, who beat Ivan Dodig and Austin Krajicek 7-5 4-6 10-6 earlier on Friday, will face Briton Joe Salisbury and American Rajeev Ram in the semi-finals.
