Stefanos Tsitsipas made it through a tough test as he defeated big-serving American John Isner 7-6 (7-5) 5-7 6-3 in the Western & Southern Open quarter-final on Friday.
Tsitsipas, the world number seven, did not create his first break point opportunity until the eighth game of the third set, but he took it with both hands to pull away in the final stages.
It was a clean match from the Greek, with just nine unforced errors with his 41 winners, while Isner committed 21 unforced errors with 54 winners and 18 aces.
Tsitsipas will play world number one Daniil Medvedev in a gripping semi-final after the top-ranked Russian was too strong for American Taylor Fritz.
Medvedev's serving dominance was the story, with 18 aces compared to Fritz's three, helping him save all six break point opportunities he faced, while only creating two himself.
After Medvedev saved three set points in the opener, he quickly claimed the first three games of the second set to cruise to victory.
Borna Coric's incredible week continued as the world number 152 defeated his third consecutive top-20 opponent, facing zero break point opportunities in his 6-4 6-4 triumph against world number nine Felix Auger-Aliassime.
The win comes after victories over Spaniards Rafael Nadal and Roberto Bautista-Agut in the previous two rounds, and he will now play Cameron Norrie for a place in his second career ATP Masters 1000 final, and his first since 2018. Coric will jump at least 86 spots when the next world rankings are released.
In the final match of the night, Norrie needed more than three hours to defeat world number four and one of the U.S. Open favourites Carlos Alcaraz 7-6 (7-4) 6-7 (4-7) 6-4.
The back-and-forth affair saw Norrie leading 4-1 in the second set, before a furious comeback led to Alcaraz winning the set and then jumping ahead 3-1 in the last, but Norrie was able to fight back once more.