French Open champion Jelena Ostapenko's preparations in the run-up to the claycourt major hit the skids in the first round of the Madrid Open.
The Latvian has failed to scale the same heights she reached last year when she emerged out of nowhere to conquer Roland Garros and was beaten 6-3 6-3 by unseeded Romanian Irina-Camelia Begu.
But if the 20-year-old harbours any hopes of repeating that run in Paris later this month, she will have to make a vast improvement on Saturday's error-filled performance.
Joining her at the exit was Venus Williams, a runner-up in Madrid in 2010. She was beaten 3-6 6-3 6-2 by Estonian Anett Kontaveit.
"I'd lost to her two times already, and so I had nothing to lose," Kontaveit said.
American 12th seed CoCo Vandeweghe's 7-5 6-0 defeat by unseeded Frenchwoman Kristina Mladenovic was the other upset of the day.
World number four Elina Svitolina, former world number one Karolina Pliskova and seventh-seeded Caroline Garcia, however, eased to victories.
Ukrainian Svitolina, the fourth seed, struck 28 winners and lost her serve just once as she brushed Alize Cornet aside 6-2 6-2
Svitolina is aiming to win her third title of the year but the 23-year-old has never progressed past the second round in Madrid.
Sixth seed Pliskova, coming off a Stuttgart Open title win last month, extended her winning run to six matches after striking 29 winners and seven aces to sweep past Elena Vesnina 6-4 6-2.
"I think I could play much better. Some parts were good, but my concentration was up and down," Pliskova said.
Frenchwoman Garcia was dominant in the first set against Dominika Cibulkova but had a tougher time of it in the second to seal a 6-1 7-5 victory.
Others to progress to the second round were Petra Martic, Kiki Bertens, Lara Arruabarrena, Julia Goerges and Daria Kasatkina.