Wimbledon champion Garbine Muguruza suffered a shock three-set defeat in her opening match in Indian Wells against world number 100 Sachia Vickery.
The Spanish third seed led by a set and 3-0 but went down 2-6 7-5 6-1 to the American qualifier, who goes on to face Japan’s Naomi Osaka in round three.
“I’ve just worked so hard for so many years and I’ve been so close,” said 22-year-old Vickery.
“This is just the most amazing night of my life and I couldn’t be happier.”
Vickery scored one of a number of shock wins in Indian Wells on Friday, with teenagers Amanda Anisimova, Aryna Sabalenka, Marketa Vondrousova and Caroline Dolehide all making progress.
Youth also held sway on the men’s side as 17-year-old Canadian Felix Auger-Aliassime claimed his first ATP main-draw win, and 19-year-old Australian Alex de Minaur his first Masters 1000 victory.
De Minaur won a gruelling encounter 3-6 7-6(3) 7-6(5) against Germany’s Jan-Lennard Struff, and Auger-Aliassime saw off compatriot Vasek Pospisil 6-2 7-6(4).
The pair join fellow teenagers Denis Shapovalov and Stefanos Tsitsipas in round two.
Top seed Simona Halep made it through in straight sets, and in-form Petra Kvitova needed more than three hours before also progressing, but Muguruza could not join them.
The Spaniard looked in complete command when she led Vickery 6-2 3-0 40-0, but would end the match with 45 errors to 22 winners as her resistance crumbled.
— WTA (@WTA) March 10, 2018
Vickery, at her highest-ever ranking of 100, dominated the second half of the contest, reeling off the last five games in a row to secure a sensational win.
“I just tried to fight every point and hang in there,” she said.
“The crowd was so amazing and got behind me, and the atmosphere really helped me even though I was feeling it a little bit physically.”
2 December 2018
Need a preview of season 2019 but short on time? We've got you covered.ATP preview1. Novak... More
16 February 2017
In the first part of our series analysing the similarities and differences between men's ... More
7 December 2018
On courtThe zenith of Halep’s season came at Roland Garros, where she finally broke thro... More