Kei Nishikori outlasted Fernando Verdasco in a close to three-hour marathon at the Miami Open on Sunday, while Milos Raonic pulled out through injury.
Japan's Nishikori, the runner-up to Novak Djokovic last year, came through a gruelling contest 7-6 (7-2) 6-7 (5-7) 6-1.
He fired 37 winners but Verdasco, aided by persistent swirling winds, used his varying pace and depth to rattle the eventual winner, inducing 48 unforced errors.
After winning the opening set in a tie-breaker, Nishikori served for the match at 5-4 in the second set but left-handed Verdasco saved a match point to break back and eventually forced a decider with a scorching cross-court backhand.
Nishikori won six of seven games in the third set to advance to the next round where he will play Argentine Federico Delbonis after he defeated Jan-Lennard Struff from Germany, 7-6 (7-5) 6-1.
Injury-plagued Raonic pulled out of the tournament with a recurrence of a hamstring injury, leaving the Canadian star saying he would not return until he is 100 per cent fit.
"It is the same muscle in the hamstring, it got progressively worse after my first round and after practising yesterday [Saturday], it was not possible to compete today without putting myself at significant risk," said Raonic, who was due to face American qualifier Jared Donaldson.
"Right now the perspective is going to change a little bit. Obviously the goal through these tournaments being on hard courts and so forth was that I can come back as soon as I feel ready.
"I think that that perspective is going to change to come back when I feel like I'm 100 per cent. So I think that will - so that could be - who knows how long? That could be in two weeks; that could be a little bit longer."
In other games, Donald Young upset Benoit Paire 7-6 (7-2) 6-4 while Nicolas Mahut came through against Guido Pella 6-4 6-3.