Top seed Verdasco cruises into quarters; Del Potro withdraws

This was the first time Kunitsyn faced the 23-year-old Isner in singles.

"It was an extremely bad first-round draw coming late into the tournament," said Kunitsyn, who had just come from Washington, where he advanced to the semifinals. "This is the last guy you want to play to get your rhythm."

The 6-foot-9 Isner next faces 6-10 second seed Ivo Karlovic in what will be their first meeting.

"That will be interesting for sure," said Isner, who made his pro debut last year. "If I somehow play well enough to win, that will be huge."

Fellow American Robby Ginepri also advanced to the second round after defeating Luis Horna 7-6 (4), 6-2.

Top seed Fernando Verdasco was scheduled to play Monday night.

Fifth-seeded Patty Schnyder defeated Jill Craybus 6-4, 7-6 (2), extending her record against the American to 4-0 in a first-round match.

Schnyder, ranked No. 15 in the world, also beat Craybus in the first round of the Beijing Olympics, 6-3, 6-2. Schnyder was eliminated in Beijing by Sybille Bammer in the second round and said she still felt the effects Monday of the 18-hour flight from China to Connecticut.

"Generally it is tough to come from Beijing," Schnyder said. "It is tough on your legs. It is just your body needs more time."

The 85-degree heat Monday didn't help either.

"I felt really weak in the second set," Schnyder said. "Luckily there was a little breeze that cooled me down. It was tough conditions."

Eighth-seeded Dominika Cibulkova retired from her match because of heat illness after losing the first set to Caroline Wozniacki 7-6 (7).