World number one Caroline Wozniacki was the biggest casualty on a day of shocks at the Madrid Open on Wednesday, falling in the third round to unseeded German Julia Goerges for the second time in two weeks.
The rangy, big-serving Goerges, who climbed to 27th in the rankings following her win against Dane Wozniacki in the Stuttgart final last month, won 6-4, 1-6, 6-3.
French Open champion Francesca Schiavone of Italy, the third seed, lost 7-6, 6-3 to unseeded American Bethanie Mattek-Sands at the Magic Box Arena while fifth seed Samantha Stosur, beaten in the final by Schiavone at Roland Garros last year, also crashed out to Russian Anastasia Pavlyuchenkova 7-6, 6-3.
Goerges mixed up her game with looping shots and then pounced on any loose balls with some aggressive drives, frustrating Wozniacki who gifted her opponent the decisive break in the eighth game of the third set when she sent the ball wide before Goerges confidently served out to love.
Goerges, who is making her debut in the Spanish capital and will play the unseeded Pavlyuchenkova on Friday for a place in the last four, said she was proud of her recent run.
"I tried to get her (Wozniacki) out of her rhythm and not let her push me and be the first to push her," she told a news conference.
"I like to play high balls to her backhand and if she goes short I have a chance to go for the shots," she added.
Ranked 21st, the 19-year-old Pavlyuchenkova is the youngest player in the top 50 and her win over Australia's Stosur, the world number eight, was her second success against a top-10 player this year.
Stosur also fell to Goerges in Stuttgart and the German attributed her recent success to the hard graft she had been putting in with coach Sascha Nensel.
"You have to keep working and believing in yourself and then you see how it ends up," she said.
"There is nothing to say it will stay like that but I am feeling confident right now," added Goerges, describing herself as an aggressive player and naming former world number one Martina Hingis of Switzerland as her tennis idol.
Victoria Azarenka continued her blistering form when she crushed Spanish wildcard Arantxa Parra Santonja 6-0, 6-3 to set up a quarter-final against Lucie Safarova.
The unseeded Czech beat Jarmila Gajdosova of Australia 6-3, 6-3 to reach her third quarter-final of the year after Kuala Lumpur and Brisbane.
Belarussian Azarenka, the highest seed left in the draw at number four, has dropped only five games in her three matches this week and is chasing a third title of the year following triumphs in Miami and Marbella.
In other third round play, China's Li Na, losing finalist at this year's Australian Open and the sixth seed, fought back from a set down to beat Italian Roberta Vinci 2-6, 6-2, 6-1.
Czech 16th seed Petra Kvitova, conqueror of second-seeded Russian Vera Zvonareva on Wednesday, and Slovakia's Dominika Cibulkova are already due to meet in the last eight.