American Coco Vandeweghe defeated defending champion and World No.1 Angelique Kerber in the fourth round of the Australian Open here on Sunday.

Vandeweghe edged past the top seed 6-3, 6-2 to advance to the quarterfinals. 

Vandeweghe will face in the quarterfinals seventh seed Garbine Muguruza who defeated Romania's Sorana Cirstea in staight sets 6-2, 6-3 in 65 minutes.

"I think it's my first win over a World No.1, I guess. I'll take it. I faked it a lot, because I was feeling a bit crap out there. You have to fake it until you make it. I just had to pick my spots and trust my game," Vandeweghe was quoted as saying by ESPN.in.