World number one Carlos Alcaraz cruised into the last 16 of the Miami Open with victory over Dusan Lajovic.
The Spanish defending champion, 19, won 6-0 7-6 (7-5) to set up a meeting with American Tommy Paul.
Alcaraz, who has won 16 of 17 matches this year and has not dropped a set in his past two tournaments, needs to win the title to stay top of the rankings.
Norwegian third seed Casper Ruud is out after a 3-6 6-4 6-4 defeat by Dutchman Botic van de Zandschulp.
After a number of upsets on Saturday, there were straightforward wins for men's seeds Andrey Rublev, Holger Rune and Taylor Fritz.
Russian sixth seed Rublev beat Serbia's Miomir Kecmanovic 6-1 6-2, while Rune, the seventh seed from Denmark, won 6-4 6-2 against Diego Schwartzman of Argentina.
Rune will play Fritz in the next round after the American ninth seed beat Canadian Denis Shapovalov 6-4 6-4.
Fourth seed Daniil Medvedev progressed without playing, after opponent Alex Molcan withdrew from the tournament.
In the women's draw, Swiss ninth seed Belinda Bencic was beaten 7-6 (10-8) 6-3 by 18th seed Ekaterina Alexandrova.
Alexandrova will face Bianca Andreescu in the fourth round following the Canadian's 6-4 6-4 win over Sofia Kenin.
Australian Open winner Aryna Sabalenkadefeated Marie Bouzkova 6-1 6-2 and next plays Barbora Krejcikova, who beat Madison Keys 7-6 (7-4) 6-3.
Meanwhile, Wimbledon champion Elena Ryabkina edged out Paula Badosa 3-6 7-5 6-3, but Czech 17th seed Karolina Pliskova lost 6-1 6-2 to compatriot Marketa Vondrousova.