MEMPHIS, Tenn. (AP) -- John Isner served up 26 aces in beating Japan's Yoshihito Nishioka 4-6, 6-3, 6-4 on Wednesday night to reach the quarterfinals at the Memphis Open.
The second-seeded American managed only five of those aces in dropping the first set. Isner, making his debut at this event at The Racquet Club, bounced back by serving up 11 aces in the second set where he won all 15 points on his first serve. He had 10 more aces in the third set winning 17 of 18 points on first service.
American Ryan Harrison upset No. 3 seed Sam Querrey 6-3, 6-1 in 54 minutes. Harrison won the first five games and broke Querrey twice in taking the first set 6-3. Then he broke Querrey twice to go up 4-0 in the second set before finishing out the match.
Harrison will play Damir Dzumhur of Bosnia-Herzegovinia, who was the first to advance to the quarterfinals by upsetting seventh-seeded Steve Darcis of Belgium 7-6 (2), 6-4.
Donald Young beat fellow American Reilly Opelka 7-6 (3), 6-3 earlier Wednesday. Nikoloz Basilashvili of Georgia beat Australia's Jordan Thompson 6-3, 6-0, and will play top-seeded Ivo Karlovic on Thursday. Mikhail Kukushkin of Kazakhstan downed Germany's Benjamin Becker 6-3, 6-4.