Nadal could potentially take on world No.2 Murray in the semi-finals at Flushing Meadows for the second successive season.

The Spaniard, though, has been struggling with an abdominal muscle injury - with Nadal needing treatment on the way to victory over Nicolas Almagro in the third round.

However Murray, who faces Marin Cilic in the fourth round on Tuesday, insists that he is focused on his own games and not whether Nadal can come through his clash France's 13th seed Gael Monfils unscathed.

"I knew he had that problem since Montreal or whenever he did it," Murray said.

"He's had the tape on his abs. Being in the locker room, we obviously can see that.

"You never now how bad it is. To me, after he had the treatment, from what I saw, didn't look like it affected him that much. Maybe lost one more game after that.

"You never know, because things can get better in a couple of days, or sometimes they get worse. You just have to focus on your own matches not what's going on in the other players."

Murray has so far overcome Ernests Gulbis, Paul Capdeville and Taylor Dent in New York - and the 22-year-old Scot believes the variety of styles will help him ahead of his clash with 16th seed Cilic.