DEFENDING champion Angelique Kerber crashed out in the fourth round in Melbourne after being blown away by American Coco Vandeweghe.

Kerber was the second top seed to falter at the Australian Open yesterday after Andy Murray’s loss to Mischa Zverev in the men’s tournament.

Vandeweghe was also an unexpected – entirely worthy victor – on Rod Laver Arena, winning 6-2, 6-3 in just 68 minutes to book a quarter-final showdown with Garbine Muguruza.

Ranked 35th in the world, the American lost in the first round here 12 months ago, just as Kerber was beginning on her path to become champion. However, the world No 1 has endured a difficult start to 2017 and her fragile confidence was ruthlessly exposed by a powerful display of baseline hitting.

“I made a lot of mistakes. I think that was not my game I play normally,” said Kerber. “It was a tough match and, of course, I’m disappointed. But I was not feeling the ball at all tonight. I was not playing good from the first point.”

It is the first time Vandeweghe has made the quarter-finals on this tournament and the 25-year-old celebrated her win by holding her arms outstretched and shrugging her shoulders.

“In terms of career wins, this is high,” Vandeweghe said. “It’s the first time I’ve ever beaten a world No 1 – doing it at a grand slam makes it sweeter.

“I wasn’t feeling confident, I guess I faked it. I was nervous, but I knew I had a chance.”

British No 1 Johanna Konta will continue her aspirations of reaching the last eight when she faces Ekaterina Makarova of Russia in the last 16 of the women’s tournament today.