Djokovic advances, Fish out at U.S. Open

NEW YORK, Sept. 5 (UPI) -- Top-ranked Novak Djokovic survived a fourth-round challenge and American Mardy Fish lost his bid for the quarterfinals Monday at the U.S. Open.

Djokovic improved to 61-2 this year with a 7-6 (16-14), 6-4, 6-2 victory over Ukrainian Alexandr Dolgopolov, overcoming a balky first set in which the Serb star needed a 30-point tiebreak to eke out a win.

Dolgopolov piled up 44 unforced errors en route to the loss.

Djokovic goes on to play fellow Serb Janko Tipsarevic in Wednesday's quarterfinals.

Fish was sent packing after losing in five sets to 11th-seeded Frenchman Jo-Wilfried Tsonga 6-4, 6-7 (5-7), 3-6, 6-4, 6-2.

Fish saved three match points but Tsonga finally capped the evening match overhand slam.

Also Monday, 20th-seeded Janko Tipsarevic reached his first-ever Grand Slam quarterfinal after defeating Juan Carlos Ferrero 7-5, 6-7 (3-7), 7-5, 6-2.