Defending champion and top seed Novak Djokovic overcame a slow start to see off Sam Querrey en route to the third around at the Western & Southern Open.
Djokovic – playing for the first time since winning Wimbledon – claimed a 7-5 6-1 victory over Querrey at the ATP Masters 1000 event in Cincinnati on Tuesday.
While Djokovic made a brief appearance in the doubles on Monday, it was the world number one's first singles match after sealing his 16th grand slam title via the All England Club in July.
Djokovic struggled early in the humid conditions, recording three double faults after going big on second serves in the opening game as he was broken by Querrey.
Querrey came out with plenty of intent, taking the match to Djokovic, who fell behind 2-0 to the American.
It was far from Djokovic's best tennis, but the Serbian star broke back and eventually took out the set thanks to 14 winners.
There was plenty of emotion from Djokovic, who cruised in the second set thanks to a pair of breaks as he awaits Pablo Carreno Busta or John Isner in the last 16.