Johanna Konta has been knocked out of the Qatar Open at the last-16 stage by Angelique Kerber.
The British number one raced through the first set but was unable to build on her promising start as Kerber responded emphatically to secure a 1-6 6-1 6-3 success.
The German's reward for seeing off the 10th seed is a quarter-final meeting with world number one Caroline Wozniacki.
Denmark's Wozniacki overcame Monica Niculescu in straight sets to reach the quarter-finals.
The Australian Open champion had to dig deep against the Romanian in the first set, but the second was far easier and she eventually progressed 7-5 6-1.
Petra Kvitova claimed a 10th straight win to overcome Elina Svitolina 6-4 7-5, while qualifier CiCi Bellis shocked defending champion Karolina Pliskova.
Australian Open runner-up Simona Halep provides the next challenge for for the 18-year-old American, while Julia Goerges, Garbine Muguruza and Caroline Garcia are also through.
