Stefanos Tsitsipas will play Matteo Berrettini in the Swiss Open semi-finals, after seeing off Fabio Fognini in straight sets on Friday. (More Tennis News)
The two-time major finalist, who is making his first appearance in Gstaad, took 66 minutes to wrap up a 6-4 6-3 victory over the Italian on Roy Emerson Court.
Though he relinquished an early break in the opening set, Tsitsipas claimed a crucial one at 5-4 to edge his nose in front.
Despite seeing another early break cancelled out in the second set, the Greek managed to earn another, and eventually progressed to the last four in comfortable fashion.
"My returns worked pretty well, I was very consistent with them," he said. "I insisted on staying back throughout the match and giving it a bit of a loop, trying to get the angles from the very beginning. It worked pretty well.
"I'm happy with how I started serving towards the end of the match. In the beginning, I was still trying to figure out how I was going to open up the court and create opportunities on my serve. It took me a while to figure out. I unlocked the code towards the end."
Another Italian lies in wait for Tsitsipas in Berrettini, who overcame Felix Auger-Aliassime 7-6 (9-7) 7-6 (7-2).
The former Wimbledon finalist is seeking his second clay-court title of the season, having also triumphed in Marrakech, while he was runner-up to Jack Draper in Stuttgart last month.
Data Debrief: Another Italian Job well done by Tsitsipas
Reigning Monte-Carlo Masters champion Tsitsipas is through to his fourth ATP semi-final of the season, with three of those coming on clay, while recording his fifth straight victory in as many meetings with Fognini.
The Greek now boasts an impressive 14-1 record against Italian opponents on surface - his only such defeat coming against Jannik Sinner in Rome four years ago.