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).

UAE Team Emirates rider achieves third on Itzulia Basque Country opening day
Pogacar wins third Flanders crown but faces fine for running red light
Thuram and Martinez star as Inter dismantle Roma
Silva to exit Man City at end of season, assistant manager confirms
Penalty heroics help Leeds beat West Ham to reach FA Cup semis
