MASON, OHIO - AUGUST 16: Novak Djokovic of Serbia returns a shot to Lucas Pouille of France during the Western & Southern Open at Lindner Family Tennis Center on August 16, 2019 in Mason, Ohio. (Photo by Matthew Stockman/Getty Images)
The second was one-way traffic as the world number one played with relentless efficiency against an opponent who ran out of answers.
Perhaps the only concern for Djokovic with the U.S. Open looming in less than two weeks was a sore elbow which required brief treatment by his trainer late in the match.
"I managed to finish the match, had a little bit of tightness in my elbow but hopefully everything will be fine for tomorrow," Djokovic said in an on-court interview.
He will have less than 24 hours to recover for a semi-final against Daniil Medvedev, who continued his recent hot form, ousting Russian compatriot Andrey Rublev 6-2 6-3 in barely an hour.
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Medvedev, a career-high eighth in the rankings, faced only one break point.
He has made two finals in the past two weeks, losing to Nick Kyrgios in Washington and Rafa Nadal in Montreal.
In other quarter-final action, Frenchman Richard Gasquet continued his comeback from groin surgery by defeating 11th seeded Spaniard Roberto Bautista Agut 7-6(2) 3-6 6-2. Gasquet, who defeated Andy Murray in the opening round, set up a semi-final clash on Saturday with Belgian 16th seed David Goffin.
Goffin advanced when his quarter-final opponent, Japan's Yoshihito Nishioka, pulled out before their match on Friday due to illness.
Gasquet underwent groin surgery in January and returned to competition in May.
"I didn’t play for six months, so it's great to be back here and reaching the semi-finals aged 33," Gasquet told ESPN in an on-court interview.
"Goffin is a tough guy, one of the fastest from the baseline, so I will be prepared to battle and to fight."