Reuters - Defending champion and top seed Angelique Kerber was knocked out of the fourth round of the Australian Open on Sunday, losing 2-6, 3-6 to American Coco Vandeweghe on Rod Laver Arena.
The German's exit followed the defeat of men's top seed and world No. 1 Andy Murray, who lost to Mischa Zverev earlier in the evening on the same court.
The 25-year-old New Yorker is through to the quarter-finals for the first time after one of the biggest wins of her career.
Vandeweghe blasted six aces and 30 winners to overpower Kerber.
"I guess I faked (having confidence) a lot because I was feeling like crap out there," she said. "But, you know, fake it 'til you make it' .... my game plan was to execute knowing that she was going to get a lot of balls back."
The world No. 35 smashed a backhand crosscourt winner to take the single break of serve she needed to claim the opening set in 33 minutes.
Kerber, who also won the US Open last year, hit back by breaking her opponent on a double fault in the opening game of the second set but Vandeweghe would not be denied.
Taking advantage of a series of uncharacteristic Kerber errors, Vandeweghe ramped up her big forehand to break back for 3-3 and another backhand gave her the opportunity to serve for the match.
Kerber was by now looking broken and sealed her fate when she looped a return far beyond the baseline.
Vandeweghe, who celebrated her biggest career victory with a shrug of the shoulders, moves on to meet Spanish seventh seed Garbine Muguruza in the last eight.
"Last year I came here and didn't even win a match and here I am now," Vandeweghe added. "It's confidence having a full off-season with no injuries .... I set a goal for this tournament to make the quarter-finals."