NEW YORK – Serbia’s Novak Djokovic, the current world number one in men’s tennis, has failed to defend his US Open title after losing to Stanislas Wawrinka of Switzerland 6-7 (1-7), 6-4, 7-5, 6-3 in the final early Monday.

Wawrinka won after nearly four hours of play to claim his third career Grand Slam title.

Djokovic is now 24-5 head-to-head against Wawrinka.