(UPDATE) CINCINNATI — Carlos Alcaraz let loose his frustrations with a violent racquet smash in a 4-6, 7-6 (7/5), 6-4 defeat on Friday (Saturday in Manila) at the ATP and WTA Cincinnati Open that he called the "worst match" of his career.

The reigning Roland Garros and Wimbledon champion could not match the wily skills of 37-year-old French opponent Gael Monfils, two decades in the game and a threat to any young gun.

"It was the worst match that I ever played in my career," Alcaraz said. "I couldn't play.

"I don't know what happened. Honestly, I couldn't, I couldn't control myself. I couldn't be better. It was impossible to win, and that's all."

The Spaniard added: "I came here thinking I'm going to feel good. I'm going to put in a good tennis, because I know how to play on this court."

Alcaraz said he had never before broken a racquet in anger but this match was the exception.

The ATP number three and 2023 Cincinnati runner-up heads to the US Open starting a week from Monday without a hardcourt win and only one second-round summer cement match in his legs.

Monfils then started a third-round catch-up match only hours after his victory, but ran out of puff as Holger Rune scraped out a 3-6, 6-3, 6-4 comeback victory.

While frustrated second seed Alcaraz was fuming at his form and occasionally screaming at his team, world number one Jannik Sinner celebrated a quiet 23rd birthday, with fate handing him a present in the form of a walkover.

The Italian advanced effortlessly into the quarters when Australian opponent Jordan Thompson withdrew before their match with a rib injury.

Sinner next gets a rematch of last week's quarterfinal in Canada, which he lost to Andrey Rublev. The Russian finished a rain-delayed match over Brandon Nakashima 7-6 (7/5), 6-1.

Third seed Alexander Zverev advanced into the last eight over Spain's Pablo Carreno Busta 7-5, 7-6 (8/6).

No. 5 Hubert Hurkacz continued his quick return from July knee surgery with a 6-3,3-6, 6-1 defeat of Italy's Flavio Cobolli.

The poor run of form for seventh seed Casper Ruud continued as the Norwegian went down 6-3, 6-1 to Felix Auger-Aliassime in 68 minutes, with the Canadian sending down 14 aces.

Women's top seed Iga Swiatek defeated Marta Kostyuk for the second time this season, powering into the quarterfinals 6-2, 6-2.