London - French Open runner-up Lucie Safarova was sent tumbling out of Wimbledon in the fourth round on Monday by unseeded American Coco Vandeweghe.
Vandeweghe, the world number 47, edged out the Czech sixth seed 7-6 (7/1), 7-6 (7/4) on Court 3 to reach the quarter-finals of a major for the first time.
Vandeweghe took the fourth round contest to match point with an ace, then won it with an unreturned serve.
The 23-year-old faces either fourth seed Maria Sharapova, the 2004 champion, or unseeded Kazakhstani Zarina Diyas in Tuesday's quarter-finals.
Safarova, 28, reached the semi-finals at Wimbledon last year and made it to her first Grand Slam singles final last month when she lost to Serena Williams in the French Open final.
Vandeweghe, meanwhile, had never been beyond the third round of a Grand Slam before this year's Wimbledon.
Safarova was the third seed in a row she has downed, after defeating Karolina Pliskova and Samantha Stosur on her way to the fourth round.
Beating Safarova is only the fourth time in 17 attempts that Vandeweghe has overcome a top 10 player.