Roger Federer: John Isner aims subtle Miami Open dig with Novak Djokovic claim

Federer broke Isner three times in a first set which he dominated 6-1.

The 20-time Grand Slam winner then took advantage of Isner’s foot injury to break in the final game of the second set to win 6-4.

The American was asked about how good he felt Federer’s returning was throughout their clash.

But he brought up Djokovic’s ability to put the opponent on the back foot.

“Yeah, there have been some players [who can return my serve well],” Isner said.

“[Federer] just does it a little bit differently. He just kind of blocks it back.

“Whereas Novak, when he's locked in, he just kind of rips it back, doesn't block it too much.

“Roger was standing in close, as well, just reacting very well and very fast to my serve. I mean, he's something else.”

Isner picked up a nasty foot injury midway through the second set and there were hints that he may not be able to continue.

He battled through the pain to finish the match, although never really tested Federer in the latter stages.

“Somewhere along in the first set I started feeling some pain on the top of my foot, and it didn't go away. It only kept getting worse,” Isner added.

“It's a terrible feeling, because you're on an island out there, and, you know, you have no team-mates to hide behind and going up against the greatest player ever, you know, playing in this incredible atmosphere, and my foot's killing me.

“Not that I would have won the match, anyways, let's make that clear.

“I think I could have made for a more interesting match and one that was a little more fun.

“Look, Roger was too good. In the first five games, I was fine. Nothing was bothering me. He was all over me.

“Then, you know, this weird pain on the top of my foot, we'll see what is. I'm hoping it's nothing, but we'll see.”