Defending champion Milos Raonic advanced to the quarterfinals of the Brisbane International with 6-3, 6-2 win over Diego Schwartzman on Thursday.
The top-seeded Raonic, who had a first-round bye, fired 12 aces in the 70-minute, second-round match and had four service breaks, including three in the second set. He dropped his own serve during an exchange of breaks to start the second set.
He will next meet either Rafael Nadal or Mischa Zverev, who were playing a night match.
Nadal beat Raonic in an exhibition match last week in Abu Dhabi and has a 6-1 lead in career head-to-head meetings, but the Canadian was still looking forward to facing the Spaniard.
"It's a great task," Raonic said. "I feel like I'm doing a lot of things well and, hopefully, I can match up and play some good tennis."
Fourth-seeded Dominic Thiem had a 7-6 (5), 6-3 win over Australian wild-card entry Sam Groth to move into a quarterfinal against No. 7-seeded Grigor Dimitrov, a 6-2, 6-4 winner over Nicolas Mahut.
In women's quarterfinals, French Open champion Garbine Muguruza came back from a 4-1 deficit to beat fifth-seeded Svetlana Kuznetsova 7-5, 6-4 to set up a semifinal against Alize Cornet, who ousted second-seeded Dominika Cibulkova 6-3, 7-5.
Cibulkova was playing her second match since clinching the season-ending WTA Finals title.