Novak Djokovic wasn’t quite ready for prime time in his first match since Wimbledon. “I really was surprised how bad I was feeling.” In the past, Djokovic might have brushed an early dip aside and chalked it up to first-round nerves. But not at 38.

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