US Open 2015: Roger Federer through to Last Eight
Five-time champion Roger Federer won a battle of the serves to beat John Isner in round four of the US Open.
Swiss Federer, seeded second, won 7-6 (7-0) 7-6 (8-6) 7-5 and set up a quarter-final against French 12th seed Richard Gasquet.
Isner had not lost his serve for the entire tournament, until his very last service game.
The American had held on for 56 straight service games until Federer, who had already won two tie-breaks, clinched the match when Isner sent a volley wide
"John has one of the best serves in the game, especially the pace on his second serve, which is unreal," said Federer.
"I guess you've got to hang around and make sure you don't drop your own serve."
The 34-year-old, chasing an 18th major title, goes on to face Gasquet, who beat Czech Tomas Berdych 6-2 3-6 6-4 6-1.
French Open champion Wawrinka earlier beat Young 6-1 1-6 6-3 6-4 on Arthur Ashe Stadium.