Novak Djokovic kept alive his hopes of ending Roger Federer’s dominance at the US Open by defeating Czech Republic’s Radek Stepanek 6-7 (4), 7-6 (5), 7-5, 5-7, 7-6 (2) Friday, in the equal-longest U.S. Open singles match in the fifth-set tiebreak era.

``I am totally exhausted. No energy,'' Djokovic said. ``I smell my shoes - they are so stinky.''

The two played 63 games, 356 points in a match which lasted 4 hours and 44 minutes, the most at the U.S. Open since 1979. That year, John Lloyd and Paul McNamee played the same number to set the tournament record for games in a singles match since tiebreakers were introduced in 1970.

The man who emerged victorious after clashes with both Rafael Nadal and Federer en route to winning the ATP Masters Series in Montreal three weeks ago needed a fifth-set tie-break to finally beat world number 35 Stepanek.

The third seed Serb will now play Juan Martin del Potro in round three after the Argentinean easily disposed of Austria’s Jurgen Melzer 6-3 6-1 6-4.

It was a great day for Serbia as No. 3 Jelena Jankovic and No. 5 Ana Ivanovic also outplayed their opponent to reach the women's fourth round.

Only Janko Tipsarevic was forced to abandon the match because of an injured rib muscle. He was loosing anyway 6-2, 6-3, 3-2 against No. 2 Rafael Nadal.