New York –

World No. 1 Carlos Alcaraz finished off an exhausted Alexander Zverev 6-3, 6-2, 6-4 on Wednesday to move into the U.S. Open semifinals where he will take on Daniil Medvedev in an intriguing clash featuring the last two champions at Flushing Meadows.

Three-time champion Novak Djokovic and 20-year-old Ben Shelton booked their spots on Tuesday.

There were questions about how prepared Zverev would be to face the energetic Alcaraz after playing the longest match of the tournament — a nearly five-hour, five-set marathon against Jannik Sinner in punishing conditions on Monday.

Zverev, a finalist in 2020, showed up ready to fight, but the tank emptied quickly, with the No. 12 seed unable to keep pace as Alcaraz stepped on the gas to pull away for a straightforward win.

Alcaraz had only four break point chances throughout the entire contest but made each one of them count.

"He (Zverev) was struggling a lot, he was working really hard to come back at his best and finally we all see him showing his best tennis," Alcaraz said.

"We enjoy his game so we are really happy to have him back."

On another hot, steamy day, with temperatures around 32 Celsius (mid-90s Fahrenheit), Medvedev reached the last four by beating No. 8 seed Andrey Rublev 6-4, 6-3, 6-4 but was unhappy about playing in such difficult conditions.

"You cannot imagine, one player is going to die and then they're going to see," he said to the camera while wiping off sweat in the third set.

By the time Alcaraz and Zverev appeared at Arthur Ashe Stadium for the late match, much of the sting had been taken out of the brutal conditions.

Zverev, with his booming serve finding the mark, was able to keep pace with Alcaraz through the early part of the first set.

Alcaraz capitalized on his one break chance of the opener to go up 5-3 and then quickly held serve to take control.

As Zverev's resistance dropped, Alcaraz broke again early in second, delighting the crowd with some highlight-reel shots and twirling his racquet like a baton.

Another break to get in front 5-2 and a hold of serve left Alcaraz with a big smile and Zverev calling for a medical timeout.

He returned for the third set with a heavily strapped groin and fought on bravely until Alcaraz grabbed another late break before serving out for the win.

While Shelton is the last local hope in the men's draw, there is growing excitement over the possibility of an all-American women's final after Madison Keys beat Wimbledon champion Marketa Vondrousova 6-1, 6-4 to join compatriot Coco Gauff in the last four.

Keys played in the last all-American final at Flushing Meadows in 2017, losing to Sloane Stephens, and the only remaining obstacle between her and a return to Saturday's championship match is second seed Arya Sabalenka, who crushed China's Zheng Qinwen 6-1, 6-4.