Andy Murray falls to stunning defeat to Mischa Zverev

And to round the night's play off, women's number one Angelique Kerber was ousted by Coco Vandeweghe.

Murray cut a discombobulated figure as Zverev served and volleyed his way to the first set but a rethink from the world number one saw him into a three-game lead in the second.

Zverev regrouped and managed to get back on serve, but Murray dug deep to break again and level the match as the clock hit the two-hour mark.

However, it was Zverev who put together an impeccable third set consisting of 13 winners, one unforced error and two breaks of the Murray serve to put himself within a set of the next round.

There were no signs of nerves from world number 50 Zverev as he broke in the opening game of the fourth set, and the 29-year-old saw it out to record the biggest win of his career after just over three hours and 30 minutes on court.

"He deserved to win because he played great when he was down, and also in the important moments," said Murray, who had lost five finals at Melbourne Park, four of them to the Serbian.

"I was kind of behind in the last couple of sets the whole way (but) I have had tough losses in the past and I have come back from them."

With Novak Djokovic falling to Denis Istomin in the second round on Thursday, the men’s side of the draw enters the quarter-final stage without its top two seeds.

"I was in a little coma," Zverev said on court afterwards.

"I just served and volleyed my way through it. "There were a few points where I don't know how I pulled it off but somehow I made it.

"I got excited. It was easy to stay aggressive but it was definitely tough to stay calm ... I was surprised at how I managed to get so many first serves in.

"It means the world to me and it means a lot that my family is here and my box is full."