Djokovic remains unbeaten at Turin

Novak Djokovic has battled to a three-hour victory over Daniil Medvedev to remain unbeaten at the ATP Finals in Turin.

Djokovic was already guaranteed to top the group and play Taylor Fritz in the semi-finals on Saturday but he dug deep to avoid defeat, completing a 6-3 6-7 (7-5) 7-6 (7-2) victory after three hours and 11 minutes.

The 35-year-old was clearly struggling physically late in the second set and into the third and Medvedev served for the match at 5-4 in the decider, but Djokovic found a way back.

The Serbian told Amazon Prime Video: "Daniil and I had some battles in the past and I knew coming into the match today it's going to be his last match of the season and he is definitely not going to want to finish the season with a loss.

"I started off very well, had my chances early in the second. He just played very well in those decisive moments. I didn't feel physically so well in the third set to be honest, I struggled a lot staying physically there.

"I'm really proud of being able to find that last drop of energy and necessary focus in order to come back into the match.

"This match against one of the greatest rivals I have today was very important regardless of the fact I'd qualified already and I really wanted to win."

Medvedev, who won the title in 2020 and reached the final again last year, leaves Turin having lost each of his three group matches in deciding tie-breaks.

In the late game, Andrey Rublev produced a stunning come-from-behind victory to down Stefanos Tsitsipas 3-6 6-3 6-2 to reach the last four.

Tsitsipas came out firing to dominate the first set, pouncing on a shallow ball from Rublev to crush a forehand winner for the early break and a 3-1 lead as the fiery Russian's temper began to boil over.

The Greek claimed the set when Rublev failed to put one of his second serves into play and it appeared the Russian might go quietly from there.

Instead, Rublev cut down on the errors in the second set and let out a mighty roar when he broke Tsitsipas for a 5-3 lead.

Rublev saved a break point in the next game and held his fist up high when Tsitsipas' forehand went wide to level the contest at a set apiece.

From there it was Tsitsipas who struggled to keep his composure as Rublev continued to apply pressure, breaking for 2-1 in the third set and again for 5-2 on back-to-back double faults by the world No.3.

"I just kept telling myself to keep fighting, keep playing, and we'll see what happens," Rublev said.

"I was happy that I was mentally strong today and I was able to turn the match around because Stef in the beginning was hitting super hard, hitting so many forehand winners."

Next up for Rublev is a semi-final against Norway's Casper Ruud.

A straight 7-6 7-6 defeat for doubles pair Nick Kyrgios and Thanasi Kokkinakis to Croatians Nikola Mektic and Mate Pavic paved the way for Britons Joe Salisbury and Neal Skupski to face each other in the semi-finals.

Liverpool's Skupski and Dutchman Wesley Koolhof, who beat Ivan Dodig and Austin Krajicek, are top seeds but would have exited had the Australians prevailed.

Instead they will now face Salisbury and his American partner Rajeev Ram in a rematch of the US Open final.