Swiatek burst onto the global stage in October by winning her first grand slam title in spectacular style and found herself this time as the only player in the quarter-finals previously to have gone further at any slam.
The Pole was on a winning streak at Roland Garros of 11 matches and 22 sets but a right thigh problem appeared to affect her as she fell to a 6-4 6-4 defeat against 17th seed Sakkari. The Greek is now the highest-ranked player left in the tournament and will face the Czech Republic’s Barbora Krejcikova in the last four.
Krejcikova ended Coco Gauff’s hopes of reaching a first grand slam semi-final with a straight-sets victory at Roland Garros.
Gauff has been in brilliant form on the clay and had cruised through to her first slam quarter-final but she was unable to take any of five set points in the opening set and faded badly afterwards to lose 7-6 (6) 6-3.
The 17-year-old led 3-0 and 5-3 in the opening set, as well as 6-4 in the tie-break, but each time Krejcikova battled back and she pounced on her first set point.
The disappointment for Gauff was evident as she made a poor start to the second set and she was unable to recover, smashing her racket forcefully on the court after a double fault left her 4-0 behind.
The other semi-final will be between Anastasia Pavlyuchenkova, the 31st seed from Russia, and Tamara Zidansek, the unseeded Slovenian.