Ons Jabeur’s search for her best form continued as she was beaten by Jasmine Paolini in the last 16 of the Stuttgart Open.
The world No. 9 has only won three of 10 matches this season and lost 7-6(8) 6-4 to Paolini, who next faces fourth seed Elena Rybakina.
Rybakina earlier recovered from a second-set wobble to beat Veronika Kudermetova 7-6(3) 1-6 6-4 and book her spot in the last eight.
World No. 1 Iga Swiatek and former US Open champion Emma Raducanu both play later on Thursday.
She had two set points in the tie-break but Paolini narrowly saved the first with a shot that the umpire came down to check and ruled had just caught the line.
Paolini brought up her own set point with a forehand winner and took it when Jabeur hit the top of the net and the ball went out.
Both players shared a break early in the second and had plenty of chances throughout, but once again it was Paolini who was more clinical.
After saving two break points in the eighth game, Paolini broke to lead 5-4.
She then fended off two more break points as she served out the win to reach the next round.
Rybakina battles through to quarter-finals
Rybakina was forced to dig deep in a marathon contest that lasted more than two-and-a-half hours.
The pair traded blows early in a tight opening set but Kudermetova was made to pay for failing to take three chances to break at 5-5.
She forced a tie-break and led 2-1 before Rybakina reeled off six of the next seven points to claim a one-set advantage.
Kudermetova responded emphatically by racing into a 5-0 lead and taking the contest all the way to a decider.
She then recovered from 4-1 down in the third set to level at 4-4 but Rybakina would not be denied, holding to move 5-4 ahead before breaking to seal a hard-fought victory that saw her progress into her seventh quarter-final of the season.