World No.1 Novak Djokovic began his campaign as the reigning Cincinnati Masters champion with a 7-5 6-1 victory over Sam Querrey to enter the third round on Tuesday.
The 32-year-old returned to the court for the first time since beating Roger Federer in a historic five-set final to win his fifth Wimbledon title last month.
He is aiming for a 34th Masters title at the US Open warm-up event to chase Rafael Nadal’s record haul of 35, which the Spaniard extended at the Rogers Cup on Sunday, before pulling out of Cincinnati with fatigue.
Djokovic made a poor start on serve as he made three double-faults to concede an early break.
Querrey opened up a 3-1 gap with a quick ace but Djokovic was soon back on level terms with Querrey folding his serve to even out the match at 3-3.
The 45th-ranked American made more nervous errors at 6-5 and gifted Djokovic the first set with a long forehand return, which saw the Serbian roar in celebration after overcoming a tough start to his title defence.
The 16-time grand slam winner exploded with more emotion after he outlasted Querrey to break for 3-1, which fired him up to earn a commanding position and serve for the match at 5-1.
Djokovic, who is the only man to win all nine Masters titles, rounded off the win with an ace in 78 minutes to advance to the next round, where he will play either another American in John Isner or Spain’s Pablo Carreno Busta.
Earlier Switzerland’s Stan Wawrinka battled back from a set down to defeat Grigor Dimitrov 5-7 6-4 7-6 (7-4) for a fifth straight win over the Bulgarian and a place in the second round.
The three-time grand slam champion missed two match points when serving at 5-2 in the second set and was broken twice to enter a winner-takes-all tie-break.
“I knew I could expect a tough match,” said Wawrinka. “It’s a first round and you never play your best tennis, but the most important thing is to fight. I’m happy with the win.”
Wawrinka sealed the contest with an ace after an exhausting two hours and 35 minutes and will face Andrey Rublev next after his 6-7 (7-4) 6-4 6-2 win over Georgia’s Nikoloz Basilashvili.
Russian Daniil Medvedev, who lost to Nadal in his first Masters final at the Rogers Cup, bested Britain’s Kyle Edmund to face Frenchman Benoit Paire, who advanced after Fernando Verdasco retired at 6-4.
But Spain’s Roberto Bautista Agut is through following a 7-6 (8-6) 6-3 win over Poland’s Hubert Hurkacz to face American Frances Tiafoe, who dismissed France’s Gael Monfils 7-6 (9-7) 6-3.