Andrey Rublev opened his ATP Finals campaign with a gripping 6-7 (7-9) 6-3 7-6 (9-7) success over compatriot Daniil Medvedev in Turin.

The sixth seed came from behind to beat his fellow Russian in a match lasting over two and a half hours to put himself top of the Red Group, with the pool's other two players, Novak Djokovic and Stefanos Tsitsipas, playing later on Monday.

Rublev got off to a fast start, securing a break to put himself 4-1 up in the first set. However, Medvedev saw off two set points to take it to a tie-break, before fending off five more set points on his way to taking an extraordinary opener.

World number seven Rublev hit back with two breaks in a strong second set to level the match, Medvedev not helping himself with six double faults.

Medvedev, the fourth seed, cut down the errors in a tight final set that did not see a solitary break of serve as a tie-break was required to settle an absorbing contest.

But after a remarkable final stand from Medvedev that saw him save four match points, Rublev finally got over the line make a winning start.

ACES/DOUBLE FAULTS

Medvedev - 24/8

Rublev - 9/1

WINNERS/UNFORCED ERRORS

Medvedev - 46/26

Rublev - 38/24

BREAK POINTS WON

Medvedev - 1/2

Rublev - 3/9