LONDON (AP) American John Isner fought off the challenge of former U.S. Open champion Juan Martin del Potro to win 7-6 (2), 6-4 and reach the second round at Queen's Club on Wednesday.
His 25 aces brought his total for the year to 513, more than any other player on the ATP Tour, and he appeared to master the slippery surface better than his Argentine opponent.
After falling early in the match Isner settled, but del Potro fell at 4-3 in the second set and then again at 4-4 and that appeared to make him a little more cautious with his movement in the final stages.
Neither player earned a break point in the opening set but Isner had to overcome a total of six break points in the second before a break at 4-4 left him serving for victory.
''As the match progressed, I definitely started feeling a lot more comfortable out there,'' said Isner. ''I figured it could be a very close match and it was. You know, it definitely came down, just as a lot of my matches do, came down to a few points here or there.''
Fellow American Steve Johnson followed his upset of fourth seed Richard Gasquet by beating French qualifier Adrian Mannarino 4-6, 6-3, 6-4, and he will face Marin Cilic of Croatia in the quarterfinals after the fifth seed beat Serbian Janko Tipsarevic 6-4, 6-2.
Milos Raonic beat Nick Kyrgios of Australia 6-7 (5), 6-4, 6-4, resuming the match on one set each after poor light ended play Tuesday.
Playing his first tournament under the guidance of three-time Wimbledon champion John McEnroe, the third seeded Canadian broke to lead 5-4 when his opponent double-faulted but had to fight off two break points as he served for the match.
Also in the first round, British wild card Kyle Edmund defeated eighth-seeded Gilles Simon of France 6-4, 3-6, 6-1. Paul-Henri Mathieu of France was also stretched to three sets before overcoming Daniel Evans of Britain 7-6 (8), 6-7 (6), 6-3.