Coco Gauff ousted by Emma Navarro from U.S. Open in fourth round

Defending champion Coco Gauff became the latest big-name casualty to exit the U.S. Open when Emma Navarro won their fourth-round match 6-3, 4-6, 6-3 to beat her stunned American compatriot 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 stunned the crowd at the Arthur Ashe Stadium with an aggressive and dominant all-round display that had Gauff searching for answers.

Gauff was her own worst enemy, however, especially on serve where the 20-year-old third seed struggled and had 19 double faults – as many as she had in her first three matches combined – while she also made 60 unforced errors.

Navarro's victory moved her into a second Grand Slam quarterfinals 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. Badosa beat Wang Yafan of China 6-1, 6-2 at Louis Armstrong Stadium on Sunday.

"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.

"It was tough losing the second set," Navarro said. "I had chances. I was up 30-love at 4-3 and then had a little bit of a lull there. But I was able to regroup after the second set and just come into the third set with a fresh mindset. I wanted to play aggressive tennis and I think I was able to do that."