Top seed Alexander Zverev churned out an opening win over Chinese wildcard Wu Yibing 6-4, 7-6 (7/4) at the Shanghai Masters on Friday to advance into the third round.
A dive left the German grimacing and grabbing his left ankle during the 11th game of the second set, with Wu, ranked 113th in the world, going up 6-5.
But the 29-year-old held serve and forced a tie-break, capitalising on a series of errors to win on his second match point when the home hope fired long.
"Credit to him, he was playing amazing tennis," Zverev told the crowd afterwards.
"He hits every ball as hard as he can," he added in another on-court interview, crediting a reliable serve for his straight-sets win.
Zverev, the world No 2, is on track to end the year with the top ranking after Jannik Sinner announced he was ending his 2026 season due to injury.
Zverev next faces Quentin Halys of France, who downed Belgium's Alexander Blockx in three sets.
Earlier, third-seeded Ben Shelton beat Germany's Daniel Altmaier 6-3, 7-6 (8/6) and will play France's Arthur Gea in the third round.
"Tough match-up," said the American, who double-faulted five times across the gritty two-hour match. "Happy with the way I finished."
It was a fitting birthday present for Shelton, who turned 24 on Friday, though he hinted he may pass on indulging, telling an on-court interviewer: "I hate cake."
Frenchman Adrian Mannarino upset sixth-seeded Flavio Cobolli 6-1, 4-6, 6-3.
Cobolli, the French Open finalist, twice fell to the ground as he failed to convert two break points in the last game.
The Italian, 24, saved a match point with a well-placed volley but could not stay afloat as 38-year-old Mannarino kept him running and forced him into a backhand he could not return.
Mannarino, ranked 83rd, will face either Karen Khachanov or Arthur Fery in the next round.
Elsewhere in the draw, Japanese qualifier Rei Sakamoto beat Russia's Andrey Rublev 6-4, 6-4.
Sakamoto, the world number 137, will next play ninth-seeded Alex de Minaur, who advanced after his opponent Alex Molcan withdrew before play.