Alexander Zverev defied a foot problem to book his place in the third round of the Shanghai Masters on Saturday, beating France's Valentin Royer 6-4, 6-4.
The world number three from Germany had a blistering start, breaking Royer in the first game and then hitting three aces to easily hold the second.
The play settled as the Frenchman found his feet, but a crucial stumble saw him miss a break point in the eighth game, and Zverev took the set.
Both players missed chances to break in the second, wowing the crowd with multiple tense rallies.
Zverev finally broke in the ninth game then held the last game to win, despite having to take a medical break after limping off court.
"It's not a nice feeling to finish a match like that," Zverev said afterwards, wincing.
"I'm happy to be through in two sets and I'll keep fighting through."
World number seven Alex de Minaur is through to the next round after comfortably dispatching Argentina's Camilo Ugo Carabelli 6-4, 6-2.
But Russia's Andrey Rublev, ranked 14th in the world, was upset by qualifier Yoshihito Nishioka 2-6, 6-1, 6-4.