London - Mike Bryan and Jack Sock won the ATP Finals doubles title in thrilling fashion on Sunday, coming from a set down to beat French pair Pierre-Hugues Herbert and Nicolas Mahut 5-7, 6-1, 13-11.
In an entertaining match at London's O2 Arena, both teams exerted consistent pressure on their opponents' serve until Bryan and Sock buckled in the seventh game.
The fifth seeds broke back immediately to level at 4-4 but remained vulnerable on their own serve and succumbed again in the 11th game, squandering opportunities of their own in the following game to lose the first set 7-5.
The American pair, who lost 6-2, 6-2 to their eighth-seeded opponents in the group stage at the ATP season finale, raced out of blocks in the second set, taking it in 24 minutes with two breaks of serve to force a match tie-break.
Bryan and Sock carved out a 9-5 lead but could not finish the match, squandering five championship points and saving one for the French before they sealed the set 13-11.
Sock, who appeared in the ATP Finals singles last year, teamed up with Mike Bryan after Bryan's twin brother, Bob, suffered a season-ending hip injury in May and won the doubles titles at Wimbledon and the US Open.
Results on the final day of the ATP Finals at London's O2 Arena on Sunday (x denotes seeding):
Mike Bryan/Jack Sock (USA/USA x5) bt Pierre-Hugues Herbert/Nicolas Mahut (FRA/FRA x8) 5-7, 6-1, 13-11
Novak Djokovic (SRB x1) v Alexander Zverev (GER x3)