Querrey -- at No. 29, the highest ranked player remaining in the field -- advanced to a tournament semifinal for the third time this season, and his first since mid-February in San Jose, Calif
In other quarterfinals at the Wake Forest Tennis Center, Alexandr Dolgopolov of the Ukraine overcame a knuckle injury on his left hand to beat Lu Yen-Hsun of Taiwan 7-6 (7), 6-3.
Dolgopolov, No. 38 in the world, advanced to a tournament semifinal for the first time this season, and will play France's Gael Monfils. Monfils topped Spain's Fernando Verdasco 6-7 (10), 6-4, 6-4.