American teenager Coco Gauff suffered a shock defeat by Katerina Siniakova in the second round at the Qatar Open.
World number three Gauff lost six games in a row in the second set and was beaten 6-2 6-4 by Czech Siniakova.
The 19-year-old Gauff was making her first appearance since an Australian Open semi-final loss to Aryna Sabalenka last month.
Despite being seeded second in Doha, Gauff could not find her usual rhythm against 27-year-old Siniakova.
After losing the opening set, last year’s US Open champion regained her composure to race into a 4-0 lead in the second set.
But Siniakova, who is a seven-time Grand Slam champion in women’s doubles, hit back spectacularly to claim one of the biggest victories of her singles career.