Pakistan, Oct. 4 -- Coco Gauff kept her composure to beat Camila Osorio 7-6 (7/4), 4-6, 6-2, overcoming shaky serving to survive the second round of the China Open on Saturday in Beijing.

The Colombian, ranked 66th, put up a formidable fight after double-faulting to lose a testy first-set tie-break, though she needed medicine to push through trouble with her back.

Osorio saved two match points but Gauff, the world number four, dug deep, rescuing long rallies with a solid backhand and cross-court saves.

"It was tough, it wasn't the cleanest," said the 22-year-old American after the two-hour-and-18-minute match.

"Just happy with how I was able to reset," she said.

She next faces either Spain's Cristina Bucsa or Chinese teenager Sun Xin...