It's been the best hard-court season of Isner's career and he has a real shot at making the last eight of a major for the first time today. He comfortably saw off Alex Bogomolov Jnr 7-6, 6-4, 6-4 on Sunday and he may have been expecting to face the former champion Juan Martin Del Potro next.

However the Argentine was ground into the New York cement by the sheer willpower of Gilles Simon who refused to miss and eventually won 4-6, 7-6, 6-2, 7-6.      

"I don't really know too much about him," Isner admitted. "But just seeing his match today, because I was waiting to go on, I was watching a lot of the match, he's definitely a counter puncher.  He does it so well.  A lot of times he'll take the air out of the ball.  He kind of wants his opponent to go for too much because he's so fast and he gets to everything.  I haven't really thought about the game plan for that yet, but I know going in that I'll have to.  I don't want to hang from the baseline with him.  Today if you saw Del Potro, he was winded out there and Simon wasn't even sweating.  He was just tapping his face with his towel.  I'm going to try to keep the points short and serve with a purpose and fight it out.  I should, you know, do fairly well."

Isner will get a thorough workout from the back of the court as Simon will be trying to keep him out there all day. It's going to be crucial for him to take some risks off the forehand side and try to get forward but he's become much more adept at doing that this season. Simon will also be a little tired after his efforts against Del Potro and Isner will be hoping the Frenchman's returns aren't quite so accurate.

Prediction: Isner in four.