It continued an extraordinary Roland-Garros for Greece as the 17th seed matched good friend Stefanos Tsitsipas’s charge to the last four in the men’s singles.
“It's a big achievement, for sure. I'm enjoying… my tennis and myself. I have people around me telling me it was going to come. You know, they were right,” Sakkari said.
“Maybe I was the one who was telling them, I was impatient, telling them, ‘When and when and when?’ It actually came this week, so I'm happy about it.”
The draw was already blown wide apart as both women remained the only two ranked in the top 30.
Sakkari was coming off her first victory over a top 10 player at a major – against last year’s finalist Sofia Kenin – but Swiatek had won 22 straight sets in Paris and was a heavy favourite to defend her first major as the only top-16 seed in the quarter-finals.
That winning streak of sets was promptly broken on Court Philippe-Chatrier as Sakkari saved a break point on a bold, kicking second serve and secured the opener on a heavy backhand.