Serbian star Novak Djokovic won the Red Group and Russian Andrey Rublev notched the other semifinal berth from the group at the Nitto ATP Finals on Friday in Turin, Italy.
Djokovic entered the season finale event as the seventh seed but became the only player in the field to finish round-robin action 3-0 after he outlasted Russian fourth seed Daniil Medvedev 6-3, 6-7 (5), 7-6 (2).
Djokovic needed three hours and 11 minutes to defeat Medvedev. He had already qualified for the semifinals but clinched the group with the win.
"This match against one of the greatest rivals I have today is very important, regardless of the fact that I had qualified already," Djokovic said. "I really wanted to win. Daniil and I have had some battles in the past and I knew coming into the match today that it was going to be his last match of the season and he wouldn't want to finish with a loss."
Medvedev held a 16-9 edge over Djokovic in aces, but Djokovic hit 53 total winners to Medvedev's 47. Djokovic saved five of six break points to keep himself in it.
Rublev, the sixth seed, bounced back from losing the first set to take down Greek second seed Stefanos Tsitsipas 3-6, 6-3, 6-2. It was a win-and-in match for both players that pushed Rublev to 2-1 and dinged Tsitsipas down to 1-2.
"I didn't give up. I kept fighting and playing," Rublev said. "I lost my emotions a bit when I lost a stupid game at 40/0 in the first set. I let my emotions go. But then I just kept fighting and playing and you will have chances. I thought I would have chances if I just gave my best. I managed to turn the match around and I am happy to be in the semis."
Rublev broke Tsitsipas' serve three times in five opportunities and had a 36-25 edge in total winners.
The tournament continues with the semifinals. Green Group winner Casper Ruud of Norway will face Rublev, while Djokovic will take on Green Group runner-up Taylor Fritz of the U.S.
Nitto ATP Finals group standings
Green Group match record (set record, game record)
1. Casper Ruud 2-1 (4-3, 40-39)
2. Taylor Fritz 2-1 (5-3, 47-39)
3. Felix Auger-Aliassime 1-2 (3-4, 37-39)
4. Rafael Nadal 1-2 (2-4, 28-35)
Red Group match record (set record, game record)
1. Novak Djokovic 3-0 (6-1, 44-31)
2. Andrey Rublev 2-1 (4-4, 39-39)
3. Stefanos Tsitsipas 1-2 (3-5, 40-44)
4. Daniil Medvedev 0-3 (3-6, 48-57)
--Field Level Media