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).

Erratic Swiatek reaches French Open round three
Sinner eases into French Open second round
Bengaluru secure IPL final berth after win over Gujarat
Medvedev stunned by wildcard Walton in French Open first round
Zee Entertainment in talks to stream FIFA World Cup in India