Defending champion Novak Djokovic clinched his second victory at the ATP Finals, but is dependent on help from Jannik Sinner to reach the semi-finals.

Djokovic will only move into the semi-finals if the Italian, who has already qualified for the semi-finals, wins his game against the Danish young star Holger Rune, trained by Boris Becker, in the evening (9 p.m./Sky). If Rune wins, the tournament of the eight best tennis players of the year will end early for Djokovic despite his 7:6 (7:1), 4:6, 6:1 against Poland’s Hubert Hurkacz.

Djokovic (36) had more trouble than expected with substitute Hurkacz. The Pole stepped in for Stefanos Tsitsipas, who had to give up his second group game against Rune due to back problems. Although he no longer had a chance of advancing, Hurkacz showed a strong performance and made life difficult for Djokovic, especially with his serve. In total, the 26-year-old Pole hit 24 aces.

Djokovic had won in three sets against Rune at the start, but then lost in three sets against Sinner. Now the world number one has to wait to see whether Sinner will help him to the semi-finals. If he had defeated Hurkacz in straight sets, he would almost certainly have qualified for the semi-finals.