The 20-year-old Spaniard came through 6-2, 6-4 to set up a meeting with Italy’s Lorenzo Musetti.

Alcaraz is aiming for back-to-back tournament wins after his triumph at Indian Wells.

Elsewhere, German fourth seed Alexander Zverev came through a tricky opening set before defeating American Christopher Eubanks 7-6 (7-4), 6-3.

Alcaraz, who won the tournament in 2022, controlled his encounter against his 37-year-old opponent, although he was briefly threatened when he was broken when serving for the match at 5-2 up.

But the fightback was shortlived, and world number two, who was watched by Brazilian footballer Neymar, Miami Heat basketballer Jimmy Butler, and 2009 US Open champion Juan Martin del Potro, sealed victory on his first match point.

“He’s a great athlete. He reaches almost every ball,” Alcaraz said of Monfils.

“But at the same time, using my strongest shot, my forehand, I attempted to shift him about the court and gradually wear him out.

“With such iconic figures from every discipline, it can be challenging to maintain concentration on the game.

“Having them here and having a brief conversation with them is a terrific chance. Putting on a show for them is fantastic.”

Zverev stopped making unintentional mistakes, converted both of his break-point attempts, and stopped four of Eubank’s five break-point attempts.

It was a challenging game. Throughout the first set, I felt he was in charge,” he remarked. “I was simply holding on, and sometimes that’s all that’s necessary.”

Zverev denied Eubanks the opportunity to serve out the first set at 5-3, and the American was broken early in the second set by Zverev, who took a 3-0 lead. Later on, in order to finish the match, Zverev had to save three break points.

The 15th-seeded Karen Khachanov of Russia, who defeated the 20th-seeded Francisco Cerundolo of Argentina 6-1, 5-7, 7-6 (7-5) on his fifth match point, will be his next opponent.