Novak Djokovic showed he is the man to beat at the US Open with a stunning display to defeat Juan Martin Del Potro in straight sets in the quarter-finals.

The 6-2, 7-6 (7/3), 6-4 scoreline does not remotely tell the story of a match where 2009 champion Del Potro threw everything at last year's winner only to see it come back with interest.

Djokovic said: "Even though it was straight sets it was much closer than that. I was lucky in the second set. We played some incredible points."

The Serbian will now play fourth seed David Ferrer, who beat Janko Tipsarevic in another classic earlier last night, in a rematch of a last-four clash from 2007.

Djokovic lost to Roger Federer in the final that year but, with the world No.1 knocked out by Tomas Berdych, the second seed assumed the favourite's mantle.

And he showed on Arthur Ashe Stadium he is back to the form that brought him three Grand Slam titles last season.

Djokovic has now reached 10 straight Grand Slam semi-finals, and Del Potro admitted the better man won.

He said: "He's playing better every match, he's the favourite to win."

If Djokovic and Del Potro was the main event, Ferrer and Tipsarevic served up a brilliant appetiser with five sets of captivating tennis.

Ferrer won the first set reasonably easily but Tipsarevic clinched a second set tie-break, letting out a huge roar, and then won five games in a row with spectacular attacking tennis to lead by two sets to one.

Ferrer was hanging on but the Spaniard found the breakthrough in the fourth to level up.

Tipsarevic turned the tables at the start of the decider to lead once more, but a heavy fall at the end of the sixth game seemed to affect him and Ferrer hit back.

A tie-break was the only way to split them and it was the Spaniard who prevailed, dropping to the court and letting out a scream of delight as he came through 6-3, 6-7 (5/7), 2-6, 6-3, 7-6 (7/4).

Ferrer said: "It was a really tough match. Janko fought a lot and he deserved also to win today."