Russia's Ekaterina Makarova etched her name into Australian Open folklore on Monday by stunning Serena Williams 6-2, 6-3 in their fourth-round match to end the American's aura of invincibility at Melbourne Park. 

Makarova, the lowest-ranked player to reach the last 16, served it up to the 13-times grand slam champion, absorbing her firepower and returning it with interest.

The 23-year-old fired sweetly struck winners on important points and showed nerves of steel as she closed out the match on her fourth match point when 12th seed Williams, serving to stay in the match, pushed a backhand wide.

"I don't know what to say, it's an amazing feeling," Makarova said in a courtside interview after raising her arms in the air to raucous applause from the stands.

"I'm really happy that I finished in my way ... It's an unbelievable feeling."

Makarova's win snapped a 17-match winning streak at Melbourne Park for Williams, who won the 2009-10 titles but missed last year's tournament due to injury.

The win secured the Russian her first grand slam quarter-final. 

Williams, who twisted an ankle in the lead-up to the tournament, was slowed by injury in the 82-minute match on Rod Laver Arena but refused to blame it for her sensational loss to the Russian world number 56.

"She played really well, she went for broke on a lot of shots," Williams, a five-time Australian Open winner, told reporters.

"I made 37 errors and that pretty much told the story of the match.

"It was definitely hard moving to that (left) side ... I just did not serve well, it was just disastrous really.

"I never blame any injury I have because I feel like she played really well and deserved the win."

The 13-times grand slam champion was a picture of torment throughout, serving up seven double-faults and routinely pushing her ground-strokes wide.

The American's last defeat at the Australian Open was by Jelena Jankovic, who beat her in the quarter-finals in 2008. 

Kei Nishikori came from a set down to become the first Japanese man to advance to the quarter-finals of the Australian Open in 80 years when he upset French sixth seed Jo-Wilfried Tsonga 2-6, 6-2, 6-1, 3-6, 6-3 on Monday.

The 22-year-old chased down everything the powerful Tsonga was able to throw at him, while the former Australian Open finalist was uncharacteristically tentative, having his serve broken six times while he committed 70 unforced errors. 

The 24th-seeded Nishikori matched the feats of Ryosuki Nunoi and Jiro Satoh, who made the last eight of the event in 1932, and will next face fourth-seeded Briton Andy Murray for a place in the semi-finals.

Nishikori, who left Japan as a 13-year-old to train in Florida, is also the first Japanese man to reach a grand slam quarter-final since Shuzo Matsuoka advanced to that stage at Wimbledon in 1995. 

World number two Petra Kvitova shrugged off the embarrassment of one of the worst missed shot of the tournament to advance to the quarter-finals of the Australian Open on Monday with a 6-2, 7-6 victory over former world number one Ana Ivanovic.

The 21-year-old Wimbledon champion was lining up her second successive smash to win the point in the ninth game of the second set but totally mistimed the shot and the ball bounced off her arm to gift Ivanovic the game.

Kvitova, perhaps mindful that footage of the shot will shortly become an Internet hit, temporarily lost her composure and dropped her serve for the first time in the match. 

Andy Murray breezed into quarter-finals of the Australian Open on Monday after Mikhail Kukushkin retired due to injury in their third set.

Murray, who had toiled against the Kazakh in the Brisbane warm-up tournament, was leading 6-1, 6-1, 1-0 when Kukushkin said he could not continue due to a hip flexor injury, allowing the Briton to retreat from the scorching heat on Rod Laver Arena.

World number four Murray, the runner-up at Melbourne Park for the last two years, will next play Japan's Kei Nishikori.  

Murray paid tribute to his new coach Ivan Lendl who watched from the stands, saying the eight-times grand slam champion had given him a welcome shot of belief in the leadup to the year's first grand slam.

"The mental side is huge in tennis, something that I've tried to get better at over the last few years ... I feel more comfortable this year," Murray said in a courtside interview.

"I don't know if you know but in the UK we haven't won a grand slam in 100 years," he quipped with interviewer and former world number one Jim Courier.