Nick Kyrgios was warned for swearing before roaring into the third round of the Miami Open with a straight-sets demolition of Damir Dzumhur.
The volatile Australian dropped his first two service games but got into a groove to score a 6-4 6-3 win over the Bosnian on Saturday.
The 12th seed next faces up a clash with Ivo Karlovic, who broke a five-match losing streak with a 7-6 (7-4) 6-1 victory over Andrey Kuznetsov.
Kyrgios received a code violation warning from chair umpire Fergus Murphy for swearing at a spectator who called out during a point.
Roger Federer continued his impressive 2017 campaign with a straight-sets, second-round victory.
But it was far from a cakewalk for the Swiss master, who came within two points of losing the first set before breaking twice in the second for a 7-6(2) 6-3 triumph over American teenager Frances Tiafoe.
Next up for Federer is big-hitting Argentine Juan Martin del Potro, who beat Dutchman Robin Haase 6-2 6-4 in a night match at Crandon Park.
Federer has a 15-5 career record against del Potro, the 2009 U.S. Open champion.
"I would love to play against del Potro," Federer said, speaking before knowing who his next opponent would be. "We've had some epic matches against each other. I'm sure the crowd would love to see it."
Federer could be on course for a semi-final showdown with compatriot Stan Wawrinka, less than two weeks after they met in the Indian Wells final.
Top seed Wawrinka defeated Argentina's Horacio Zeballos in 65 minutes, firing seven aces in a 6-3 6-4 victory in less than favourable morning conditions.
"I'm really happy with the match today," Wawrinka told reporters. "It's quite tough conditions, raining and really windy today. It's really windy on the court, so it's never easy.
"I'm happy with the way I was moving, the way I was playing and my attitude in general was really positive," he added. "So it's a great match."
Austrian number six Dominic Thiem was the only high seed to suffer a loss on Saturday.
Thiem fell to 20-year-old Croatian Borna Coric, who overcame an embarrassing brain freeze in the final game to win 6-1 7-5.
Serving for the match, Coric stopped in the middle of a rally, challenging a line call, only to be reminded by the chair umpire that he had no challenges left.
AAP