The 14th seed is the first American to reach the final four at the Foro Italico since Reilly Opelka in 2021.

The momentum-shifting quarter-final came down to the wire, with a 15-minute final game capping off nearly two and three-quarter hours on court. Paul finally came through on his fourth match point as Poland's Hurkacz sent a return long.

The match featured 13 breaks of serve, with Paul advancing with 29 winners and 41 unforced errors; and Hurkacz having 22 and 44 respectively.

"I started well but it got away from me in the second and start of the third," Paul said. "I had to stick around in the match.

"I found the energy to get it going again. I was hitting my forehand bigger and with more intensity because Hubii can really crush the ball."

Paul will wait for an opponent from sixth seed Stefanos Tsitsipas and Chile's Nicolas Jarry.

In the women's tournament world number one Iga Swiatek faces third-seeded American Coco Gauff with second seed Aryna Sabalenka taking on 13th seed Danielle Collins of the United States for a place in Saturday's final.

Hurkacz, who knocked Rafa Nadal out in the Rome second round, was unable to get his massive serve up to speed as he faced Paul, winner over defending champion Daniil Medvedev in the fourth round.

Hurkacz won the clay title in Estoril last month and suffered only his third loss on clay this spring.