(REUTERS) - Novak Djokovic overcame some early jitters in his first match since his triumph at Wimbledon last month to see off Sam Querrey 7-5 6-1 at the Cincinnati Masters on Tuesday (Aug 13).
The defending champion and world No. 1 fired his 15th ace on match point to make up for his slow start on the sun-soaked courts.
"I made three double faults in my opening game and lost the break. I was quite a nervous at the start," he said of falling behind 2-0 against the big-serving American.
"I'm really glad to overcome a challenge like this and get myself going."
Djokovic, who defeated Roger Federer in an epic final at Wimbledon, said he needed time to recover from the surge of emotions.
"That was one of the most epic matches I've been a part of and probably the most demanding one from the mental perspective," he said of his five-set victory.
"So it really did take me some time to recharge my batteries, especially in my head. My body was fine."
Swiss Stan Wawrinka overcame Bulgaria's Grigor Dimitrov 5-7 6-4 7-6(4) in a roller-coaster first-round match.
Dimitrov clawed back from a double break down in the decider to level at 5-5 and after Wawrinka broke again, Dimitrov forced the tiebreak.
The Swiss surged into a 4-0 lead but Dimitrov rallied once more before Wawrinka closed out the match with an ace.
Young American Frances Tiafoe beat Frenchman Gael Monfils 7-6(7) 6-3 and Canadian Denis Shapovalov came from behind to see off Portugal's Joao Sousa 2-6 6-3 6-2.