Novak Djokovic improved to 19-0 in the first round of the U.S. Open, battling through some leg troubles to beat Learner Tien 6-1, 7-6 (3), 6-2 on Sunday night. Djokovic had his hands on his

The indomitable Novak Djokovic secured a first-round straight-set win over Learner Tien at the US Open to extend his Arthur Ashe record on Sunday night.

Novak Djokovic looked tired. He looked hurt. And at times Sunday night, he just looked old. Djokovic overcame all that and improved to 19-0 in the first round of the U.S. Open, battling through some leg troubles to beat Learner Tien 6-1,