World number two Jannik Sinner made a smooth start at the Miami Open, where defending champion Jakub Mensik shook off a 'horrible' first set to win his opening match.
Sinner launched his pursuit of tennis' 'Sunshine Double' in confident style with a 6-3, 6-3 victory over 76th-ranked Damir Dzumhur.
Former number one Daniil Medvedev also had a strong showing, fighting back for a 6-7 (10/12), 6-3, 6-1 victory over 19-year-old Japanese wildcard Rei Sakamoto.
Mensik, who fell in the third round at Indian Wells, righted the ship to beat Australian Adam Walton 3-6, 6-2, 6-4.
Fourth-seeded German Alexander Zverev cruised into the third round with a 6-2, 6-4 victory over 133rd-ranked American Martin Damm.
In the women's draw, Coco Gauff led the way into the fourth round, roaring back for a 3-6, 6-0, 6-1 victory over fellow American Alycia Parks.
Teenagers Mirra Andreeva and Victoria Mboko booked a last-16 meeting that will be their third clash of the WTA season.
