Emma Navarro upset defending champion Coco Gauff 6-3, 4-6, 6-3 to move into the US Open quarter-finals on Sunday, beating her fellow American for the second time in a Grand Slam this year.
Gauff had been looking to avenge her defeat by Navarro at Wimbledon, where she lost in the fourth round, but the 13th seed was high on confidence as she stunned the Arthur Ashe Stadium crowd with a dominant all-round display.
Gauff was her own worst enemy, however, especially on serve where the 20-year-old third seed struggled and had 19 double faults and 60 unforced errors.
Navarro's victory moved her into a second Grand Slam quarter-final where she will play Spain's 26th seed Paula Badosa, while defeat for Gauff will see her drop out of the top five in the world rankings.
"I lost in the first round (in the) last two years and now to be making quarter-finals is pretty insane," Navarro said. "This is the city I was born in and it feels so special to be playing here.
"Coco's an amazing player and I have a ton of respect for her. I know she's going to come back here and win this thing again one year."
Gauff started poorly, serving three double faults in her opening service game as a hush descended in the crowd before she recovered, saving four break points to level the first set at 1-1.
From then on it was mainly the self-assured Navarro dictating rallies with poise while Gauff made errors playing on the defensive, handing her fellow American a 4-2 lead when she double-faulted yet again, this time on a break point.
Gauff let out a triumphant scream when she saved a set point on serve but Navarro was almost unstoppable on her own serve, taking it to love to seal the opening set.
The second set went with serve but while Navarro was well in control, Gauff was struggling and Navarro duly broke at 3-3 with a passing shot after a mad scramble to the net.
That was just the wake-up call Gauff needed as the holder suddenly switched gears and broke twice to win three games in a row and force a decider.
Gauff's celebratory roar whipped the crowd into a frenzy but their enthusiasm quickly faded and turned into groans of disappointment when she served two consecutive double faults to give Navarro a break.
Gauff nearly threw it away at 4-2 with four double faults in one game. Two more double faults while serving to stay in the match proved to be her undoing as Navarro sealed her progress when the champion's return on match point went long.
