Top seed Aryna Sabalenka and US star Coco Gauff suffered setbacks in their Wimbledon build-ups on Thursday when they slumped to second round losses at the Berlin WTA tournament.
World No 2 Sabalenka was defeated 6-2, 7-6 (7/2) by Veronika Kudermetova whose Russian compatriot Ekaterina Alexandrova saw off seventh-ranked Gauff 6-4, 6-0.
Alexandrova and Kudermetova will meet in Friday's quarterfinals, just five days after they fought out the final in 's-Hertogenbosch.
Kudermetova had also defeated Sabalenka at the same stage in Berlin 12 months ago in three sets.
On Thursday, world number 13 Kudermetova broke her Belarusian opponent three times in her 99-minute victory.
Alexandrova, ranked at 22, successfully defended her 's-Hertogenbosch title in a dramatic three-set triumph over Kudermetova on Sunday.
Her win over Gauff avenged her loss to the American teenager from two match points up in their only previous meeting at Dubai in 2021.
After falling behind 3-1 in the first set, the 28-year-old Russian won 11 of the last 12 games to reach the Berlin quarterfinals for the second time in her career.
"Grass is not my favourite surface, but somehow I'm managing to play so well on it," said Alexandrova.
"And maybe the score looks easy, but it's never like that because she played amazing. I needed to stay focused during every single point to keep it that way. I'm just hoping I can keep this form as long as I can."
Greek sixth seed Maria Sakkari breezed past Aliaksandra Sasnovich of Belarus 6-2, 6-1 while Marketa Vondrousova also made the last eight when German opponent Jule Niemeier retired with injury from their second round clash.