PARIS – Big-serving American John Isner edged Argentine Juan Martin del Potro 6-4, 6-7 (5), 6-4 on Friday to advance to the Paris Masters semifinals for the third time in his career.
The match turned in Isner’s favor in the third game of the final set, when the 13th-seeded Del Potro squandered a 40-15 lead on serve due to a series of unforced errors.
The 2016 runner-up then fully capitalized on his opponent’s slip-up, using his massive serve to close out the victory in two hours and 10 minutes.
The ninth-seeded American faced a tense moment when serving at 30-30 in the final game, but after missing his first serve, he blasted his second into Del Potro’s body that the Argentine was unable to return.
Isner, who fired a total of 15 clean aces in the contest, smacked one last unreturnable serve on match point to book his spot in Saturday’s final four at this indoor hard-court tournament.
He will next take on Serbian qualifier Filip Krajinovic, who advanced on Friday when Spanish world No. 1 and top seed Rafael Nadal withdrew prior to their scheduled match with a knee injury.
Del Potro, meanwhile, came up just short of qualifying for the ATP Finals season-ending tournament, which will be held in London between Nov. 12-19. Strong results in recent weeks had put a Finals berth (his first since 2013) in sight for the Argentine, but he fell at the very last hurdle.
The final spot in that elite eight-man tournament will now be claimed by either Isner, fellow American Jack Sock or Spain’s Pablo Carreño Busta.
Isner and the 16th-seeded Sock, who squares off in a Friday night quarterfinal against Spain’s Fernando Verdasco, can only qualify by winning the Paris Masters.