Andy Murray out in shock fourth round defeat

World No. 1 Andy Murray will have to wait another year for a tilt at the Australian Open title after a fourth round stumble against Germany's Mischa Zverev on Sunday.

Zverev was a deserving winner, downing the Brit 7-5, 5-7, 6-2, 6-4 in a little over three and a half hours, resoundingly responding to the pressure Murray was throwing in the later half of the match to "play the best match of my life".

"I believed in myself, I believed in my game, believed that playing serve and volley against him and slicing a lot, trying to destroy his rhythm was going to work, which it did in the end," Zverev told reporters on Sunday.

Murray had his opportunities to fight back, but the response of the world No. 50, especially the shots as he came forward, the reflex volleys and pickups when the match was tight showed "he deserved to win".

"He served very well when he needed to, especially when he was behind in games," Murray told reporters.

"I was kind of behind in the last couple of sets the whole way, but the first two sets, I had chances.

"I was up a break in both of them pretty early, (but) couldn't convert my opportunities."

The round four exit ends a campaign destined for Australian Open glory after defending champion and world No. 2 Novac Djokovic was downed in a marathon five sets in round two. Murray has lost four of the last six finals in Melbourne, including the previous two to six-time champion Djokovic.

"Did I miss an opportunity? I don't know. Every year you come is a different chance, different opportunity," Murray said, adding "even had I got through this match, there was still Roger Federer and three guys that are pretty much in the top 10 in the world in my half."

"There's certainly no guarantees, even if I got through today's match, that I would have gone further.

"It's disappointing to lose, (but) I don't feel like this is any more of an opportunity than other years."

Zverev win is just a day after his younger brother, 19-year-old Alexander lost to Spanish star Rafael Nadal 6-4, 3-6, 7-6 (5), 6-3, 6-2. But, the outstanding play of the youngsters has been a theme of this year's open, with some of Australia's up and coming talent making into the later rounds.

"(It was) a tough match," Nadal said of the four hour marathon against the 19-year-old world No. 24.

But Alexander's positive influence was crucial to Zverev getting back onto the court following a series of injuries and surgery, dropping down to the bottom rungs of the ATP in 2015.

"It was my brother who said, 'you can make it back, you can be top 100 again, (and) be a great player.' I have to say thank you to him quite a lot," Zverev said.

"When you see him doing well, there's a lot of positive emotions in the family on the court, off the court.

"Even when I feel like I'm not doing too well, he's playing finals in Halle, beating Roger in the semis, it just gives me just positive emotions that I take with me to the next tournament and do well there."

Zverev will face either world No. 5 Nishikori or Federer in the quarter-finals. Enditem