Andy Murray's hopes of a first Australian Open title blew up in smoke as the world number one tumbled out in the fourth round to an inspired Mischa Zverev, while Roger Federer and Stan Wawricka advanced to the last eight.
Murray had been the outstanding favourite in Melbourne following Novak Djokovic's early exit but the Scot was woefully out of sorts on Rod Laver Arena as world number 50 Zverev sealed a shock 7-5 5-7 6-2 6-4 victory.
It is only the fourth time Murray has lost to an opponent ranked outside the top 40 at a grand slam and his first since 2007.
Zverev, who was playing his first ever grand slam fourth round, will now face either Roger Federer in the quarter-finals.
The German is a throwback to the old days of serve and volley and he simply bamboozled Murray, usually so adept at the areas of pass and lob, with a brilliant display at the net.
"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."
Zverev's younger brother Alexander, the much more fancied of the two siblings and sitting in his box, had stretched Rafael Nadal to five sets less than 24 hours before, but Mischa went one step further by inflicting arguably the biggest shock of Murray's career.
Even when he dumped a smash into the net late in the fourth his nerve did not waver, instead looking to his mother and coach in the box for reassurance.
"I always look at my mum because she smiles when I miss those balls, so I looked at her and it was okay," Zverev said.
A resilient Roger Federer showed there was life in the 35-year-old's legs as he overhauled fifth seed Kei Nishikori 6-7(4) 6-4 6-1 4-6 6-3 to book a place in the quarter-finals.
After six months out of the game, Federer's fairytale return continued under the lights of Rod Laver Arena where he emphatically quashed doubts about his fitness in three hours and 24 minutes of high-octane tennis.
Having stormed into the match after a 90-minute demolition of Tomas Berdych, Federer showed his appetite for a grind, going toe-to-toe with the fleet-footed Japanese in a match of marathon points.
He sealed the match with an imperious smash down the line and will play Zverev for a place in the semi-finals.
Stan Wawrinka's campaign for a second Australian Open title stepped up a gear on Sunday as the hard-working Swiss fended off Italian journeyman Andreas Seppi 7-6(2) 7-6(4) 7-6(4) to reach his fourth quarter-final at Melbourne Park.
The 2014 champion has done it tough in the opening week, but despite the tight scoreline, he was rarely threatened by 89th-ranked Seppi on a sunny afternoon at Margaret Court Arena.
With top seed Andy Murray crashing out only minutes before the win, Wawrinka's chances of grabbing a fourth grand slam title have been given a huge boost and he is now the highest seed in the top half of the draw.
Wawrinka now faces Jo-Wilfried Tsonga for a place in the semi-finals after he ended Dan Evans' fairytale run in the competition.
Evans knocked out world number seven Marin Cilic and then Bernard Tomic to reach his first grand slam fourth round but Tsonga proved a step too far, the Frenchman sealing a 6-7 (4/7) 6-2 6-4 6-4 victory.
Despite defeat, Evans is set to climb from 51st to 45th in the world rankings and leaves Melbourne knowing he can compete with the elite.
Tsonga, the 12th seed, goes through to face US Open champion Stan Wawrinka for a place in the semi-finals.
