Sweeting joined John Isner, Teymuraz Gabashvili and Ivo Karlovic in the quarterfinals of an American tune-up for this spring's French Open. Sweeting rallied to oust Querrey 3-6, 7-6 (7-5), 6-3.
In the quarterfinals, Sweeting will meet Gabashvili, a 7-6 (7-4), 6-3 winner over Grigor Dimitrov.
Karlovic, a former champion of this event, coasted by Igor Kunitsyn 6-4, 6-1 to set up a quarterfinal match against Isner.
Isner downed Horacio Zeballos 7-5, 6-3.
The rest of the quarterfinal spots will be decided Thursday in second-round matches featuring top-seeded Mardy Fish against Albert Ramos. Igor Andreev will meet Kei Nishikori, Guillermo Garcia-Lopez will face Somdev Devvarman and James Blake will take on Pablo Cuevas.