World number one Aryna Sabalenka cruised into the Stuttgart Open semi-finals on Saturday while two-time champion Iga Swiatek lost to Jelena Ostapenko for the sixth time in as many meetings.
Sabalenka reached the last eight without striking a ball following a bye and walkover, and took time to find her rhythm against Elise Mertens before wrapping up a 6-4, 6-1 victory.
Mertens broke for a 4-3 lead in the opening set but Sabalenka hit back right away and reeled off nine of the final 10 games to power into a semi-final showdown with Coco Gauff or Jasmine Paolini.
A beaten finalist three times in a row from 2021 to 2023, Sabalenka has never won in Stuttgart.
However, the Belarusian won't have to contend with Swiatek -- who beat her in the last two of those finals -- after the second-ranked Pole suffered another defeat by the unpredictable Ostapenko.
Ostapenko, ranked 24 in the world, won 6-3, 3-6, 6-2 in a clash of past and present French Open champions.
Swiatek has now lost all six matches against the Latvian, with Saturday's defeat the first on clay.
Swiatek came into the match with an 11-1 record on the Stuttgart clay.
But Ostapenko won the first four games and broke Swiatek's serve three times to win the opening set.
Swiatek fought back to send the match to a deciding set, but Ostapenko regained control, winning 12 of the opening 15 points on the way to victory.
Ostapenko will face Russian Ekaterina Alexandrova in the semi-finals on Sunday, with the final on Monday.
Alexandrova continued her underdog run by dumping out third seed Jessica Pegula in straight sets, 6-0, 6-4.
Pegula reached the final at the Miami Open in March and won the Charleston Open earlier in April but did not have an answer against her 22nd-ranked opponent, who knocked out Mirra Andreeva in the last 16.
After failing to win a game in the first set, Pegula saved three match points at 5-2 down in the second. She fought off two more at 5-4 but could not hold on.
Alexandrova's five WTA top 10 wins are the equal most in 2025 with Andreeva and Australian Open champion Madison Keys.