Australian Open runner-up Dominic Thiem advanced to the quarter-finals of the Rio Open with a hard-fought victory over Spain's Jaume Munar.
Top-seeded Thiem of Austria best Munar 6-7 (7-5) 6-4 6-4 in a match that took 2 hours, 41 minutes.
Thiem clinched the win by breaking the serve of a tireless Munar in the last game.
In the next round, he will face Italy's Gianluca Mager.
"I didn't play my best tennis, but it was enough," the Austrian said.
He looked recovered from a left knee injury he picked up on Wednesday after accidentally hitting one of the doors of the tennis court build in Rio's hypodrome.
Earlier, Mager topped Portugal's Joao Domingues 6-3 7-6 (7-5).
Second-seeded Dusan Lajovic of Serbia was eliminated by Lorenzo Sonego.
The Italian won 7-6 (7-5) 7-6 (7-5) and will play fifth-seeded Borna Coric of Croatia in the quarter-finals.
Coric beat home favorite Thiago Seyboth Wild 6-3 1-6 7-6 (7-5).