Carlos Alcaraz beat Daniil Medvedev in last week's Indian Wells final to return to world number oneWorld 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 last two tournaments, needs to win the title to stay top of the rankings.
Elsewhere, women's ninth seed Belinda Bencic was beaten 7-6 (10-8) 6-3 by 18th seed Ekaterina Alexandrova.
But 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 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.
In the women's draw, Elena Ryabkina edged out Paula Badosa 3-6 7-5 6-3, Bianca Andreescu beat Sofia Kenin 6-4 6-4, but 17th seed Karolina Pliskova lost 6-1 6-2 to fellow Czech Marketa Vondrousova.
