Top seeds Agnieszka Radwanska and Angelique Kerber were both dumped out of the first round of the Madrid Open on a day of giant-killings on the red clay at La Caja Magica.
Radwanska was knocked out by Slovakian Dominika Cibulkova as the world number two came unstuck on what is her least favourite surface.
Cibulkova, a former Australian Open finalist who was in the world's top 10 just over two years ago before being hit by injury, won through 6-4 6-7 (3/7) 6-3 in a clash that lasted over two and a half hours.
Pole Radwanska was not the only leading player packing their bags, though, with second seed Kerber also making a shock early exit.
Kerber had never even lost a set in four previous meetings with Barbora Strycova but the world number three from Germany saw that unbeaten run come to an end on Sunday with the Czech claiming a 6-4 6-2 triumph.
Strycova said on www.wtatennis.com: "I'm happy about my performance today. I stuck with the game my coach told me, and I was kind of in the zone and stable, which I'm happy about the most."
Seventh seed Roberta Vinci and ninth seed Svetlana Kuznetsova were also surprise first-round casualties, going down to Danka Kovinic (6-4 6-2) and qualifier Laura Siegemund (6-0 3-6 6-3 (8/6)) respectively.
Those results mean that home hope Garbine Muguruza is now the top seed left standing in the Spanish capital, the number three easing into the second round with a 6-2 7-5 triumph over Anna Karolina Schmiedlova.
Muguruza said: "In Madrid we have this extra pressure because I'm here at home. Perhaps you're a little bit more nervous because of that. But my first feeling is that I'm satisfied for winning the match, fighting, as I fought a lot."
There were also victories for the other eight seeded players in action, including numbers four and five Victoria Azarenka and Petra Kvitova, as well as Simona Halep, Carla Suarez Navarro, Timea Bacsinszky, Lucie Safarova, Karolina Pliskova and Ana Ivanovic.
Kvitova is the defending champion and also lifted the title here in 2011.
Among some of the other victors on Sunday were Madison Keys, Sabine Lisicki and Samantha Stosur.
In the men's event, Spain's Fernando Verdasco was a 7-5 7-6 (7/3) winner over Juan Monaco, while Alexandr Dolgopolov beat Steve Johnson over three sets.
Source: PA
