Aryna Sabalenka lost in the French Open semi-finals to Czech player Karolina MuchovaWorld number two Aryna Sabalenka's Wimbledon preparations suffered a blow as she was beaten by Veronika Kudermetova at the German Open.
The top-seeded Belarusian lost 6-2 7-6 (7-2) to the Russian wildcard in the second round in Berlin.
Sabalenka is the latest top-10 player to fall short at the grass-court event after defending Wimbledon champion Elena Rybakina lost on Wednesday.
American fifth seed Coco Gauff is also out after a straight-set defeat.
Russia's Ekaterina Alexandrova, who won the Libema Open last week, won 11 of the last 12 games to secure an impressive 6-4 6-0 win over Gauff in just 75 minutes.
The tournament in Berlin was Sabalenka's first since the semi-final of the French Open and she would have been hoping to get plenty of match practice on grass before her first Wimbledon since 2021.
The 25-year-old did not compete at SW19 last year after the All England Club banned Russian and Belarusian players following the invasion of Ukraine.
However, the Australian Open winner immediately fell a double break down against Kudermetova, ranked 10th in the world, and struggled to find her rhythm as she won just two games in the opening set.
Sabalenka then fell a break down in the second set and struggled through an error-strewn tie-break as Kudermetova, 26, eased into the quarter-finals.
Elsewhere, Italian fourth seed Jannik Sinner came from behind at the Halle Open in Germany to overcome compatriot Lorenzo Sonego 6-7 (4-7) 6-4 6-4 and reach the quarters.
Sinner, 21, who reached the last eight at Wimbledon last year, has needed three sets to win all his matches so far in Germany.
He will face Kazakhstan's Alexander Bublik, ranked 48th in the world, in the quarter-finals after he beat home favourite Jan-Lennard Struff 6-3 6-7 (4-7) 6-3.
