World number two Rafael Nadal has heaped praise on compatriot Tommy Robredo after he knocked Roger Federer out of the US Open.

The Spaniard shocked the Swiss in straight sets with a 7-6 6-3 6-4 victory in the fourth round at Flushing Meadows.

Following the upset, Nadal was full of praise for Robredo and insists that there are not many better feelings than beating Federer at a Grand Slam.

"He's playing great, I'm happy for him," Nadal told reporters.

"He had similar circumstances to me, he came back after a tough injury. I'm happy to see him back on the tour. He's had an amazing career, he's playing a great tournament. Winning against Roger in the US Open is amazing."

Robredo will now face Nadal in the quarter-finals of the tournament.