The Frenchman saves two set points in a second-set tiebreaker and won the match 7-5, 7-6, 7-5.
World No. 39 reaches her first Grand Slam semifinal in 37th major appearance.
The 10th seed upset the fifth seed, 4-6, 7-6 (4), 6-7 (6), 7-5, 6-4.
Bellis, the top-seeded girl, frequently shrieked at herself after bad shots, at times saying, ''Where's your game?'' and ''That is so lame!''
Switzerland will play Italy the week after the U.S. Open.
With high expectations, Tsonga bowed out early—yet again.
Teen star Belina Bencic owned the crowd, and Jelena Jankovic, in Ashe.
Wozniacki was her old, subtly disruptive self in her upset win over Sharapova.
Dimitrov buckles down, Gael stays cool, and Thiem goes mega. Plus: Monday previews.