WASHINGTON -- Two-time runner-up John Isner was beaten in his opening match at the Citi Open on Wednesday, then complained that he and fellow American Steve Johnson played on a secondary court instead of in the main stadium.
The fifth-seeded and 12th-ranked Isner failed to earn a single break point and lost to the 68th-ranked Johnson 6-7 (5), 6-3, 7-6 (6), despite hitting 29 aces.
Johnson only converted 1 of 2 break points, but that was enough to get past Isner, a finalist at Washington's U.S. Open tuneup tournament in 2007 and last year.
Isner was coming off a hard-court title in Atlanta last week.
The fourth-seeded Nishikori, who received a first-round bye, was playing for the first time since losing in Wimbledon's fourth round on July 1.
"I had some rough points ... and I knew that was coming," said Nishikori, whose next opponent in Washington is Lukas Lacko of Slovakia.
Nishikori said he could tell Querrey was "trying to be a little more aggressive" than usual, hitting big on backhands in addition to serves and forehands.
But Nishikori said he was able to end his three-match losing streak against Querrey by staying "steady from the baseline" and working to "concentrate my service game."
Nishikori is currently ranked 11th. Earlier this year, he became the first Japanese man to crack the top 10, rising as high as No. 9.
Two seeded men lost when Victor Estrella Burgos of the Dominican Republic beat No. 8 Feliciano Lopez of Spain 7-6 (5), 6-4, and Donald Young of the United States eliminated No. 17 Julien Benneteau of France 6-4, 6-3.
In women's action, Kristina Mladenovic of France beat American qualifier Taylor Townsend 6-3, 6-4, and Zarina Diyas of Kazakhstan stopped playing against Kurumi Nara of Japan because of a right elbow injury.