No. 13 seed Isner beat Filippo Volandri of Italy 6-0, 6-2, 6-3, and No. 26 seed Querrey eliminated Guido Pella of Argentina 7-6 (3), 4-6, 6-1, 6-2.
When Isner lost a first-round match in Montreal earlier this month, he dropped to No. 22, marking the first time no American man was listed in the top 20 since the start of the ATP computer rankings in 1973. Isner reached the final the next week in Cincinnati to move back into the top 20.
Querrey fell out of the top 20 at the end of July. He hasn't been past the third round in a Grand Slam since the 2010 U.S. Open.