Estonian teenager Anett Kontaveit posted a career-best win over top seed Alize Cornet in the opening round of the Collector Swedish Open.
Frenchwoman Cornet replaced Serena Williams, who she beat at Wimbledon, as the leading player in Bastad following the defending champion's withdrawal.
But her hopes of a second title of the season were ended at the first hurdle as 18-year-old qualifier Kontaveit triumphed 7-6 (7/3) 6-3.
It has been a good few weeks for the teenager, ranked at a high of 161, after she also qualified for Wimbledon and at last week's tournament in Bucharest.
Fourth seed Yaroslava Shvedova was also a first-round casualty, the Kazakh losing 7-5 6-3 to qualifier Laura Siegemund, while fifth seed Anna Schmiedlova and eighth seed Polona Hercog went out as well.
Sixth seed Annika Beck did make it through, the German winning 6-3 4-6 6-3 against Katarzyna Piter, but home hope Johanna Larsson lost 6-2 4-6 7-5 to Kaia Kanepi.
The result is a major blow for Larsson, who lost to Williams in the final last year and is now set to drop out of the top 100.