Roger Federer took one step closer to a fourth Miami Open crown after defeating Canadian teenager Denis Shapovalov.
"It was a tactical match by me... I'm happy I was able to play with variations," said the 37-year-old Swiss, who won 6-2 6-4.
"I enjoyed it. I think I played very well. I had to. Because I think when you let Denis play, he's got some serious power, and he gets rhythm going. He can really put you in uncomfortable situations."
Defending champion Isner also bested a Canadian teenager, 18-year-old qualifier Felix Auger-Aliassime, 7-6 (3), 7-6 (4).

Medvedev defends Almaty Open title to close in on ATP Finals
Rybakina brushes aside Fernandez to retain Ningbo crown
Volkanovski secures quick win over Evloev at Abu Dhabi's UFC 333
Hamilton fastest to complete Ferrari's US Grand Prix practice sweep
Gabriel shines at both ends as Arsenal ease past Everton to go level with Man City
