By Ian Ransom
MELBOURNE (Reuters) - Milos Raonic struck a blow for the next generation of men's tennis by flooring former champion Stan Wawrinka on Monday before China's Zhang Shuai became the first qualifier to reach the Australian Open quarter-finals in more than 20 years.
Second seed Andy Murray, returning to court two days after his father-in-law was rushed to hospital, hit back for the old guard in the evening session at Rod Laver Arena though, banishing Bernard Tomic, the last home hope in the singles.
Murray's win capped a banner day for Britain following Johanna Konta's advance, giving the nation men's and women's singles quarter-finalists at the same grand slam for the first time in nearly 40 years.
Melbourne Park was rocked by corruption allegations on its opening day, and a week later, integrity fears returned as a former Australian professional player pleaded guilty to match-fixing at a Sydney court.
Former world number 187 Nick Lindahl appeared in court just hours after a top global bookmaker suspended betting after heavy gambling on a mixed doubles match at Melbourne Park.
The winning doubles pair dismissed suspicions over the match after being questioned by integrity officials.
There was no questioning the commitment of Raonic and Wawrinka as the pair slugged out a three-hour 44-minute thriller in the day session on Rod Laver Arena.
Long seen as a threat to the Novak Djokovic-led establishment, 25-year-old Raonic showed ice in his veins to fend off the 2014 champion 6-4 6-3 5-7 4-6 6-3 after the 30-year-old Swiss roared back from two sets down.
Unveiling an aggressive serve-volley game, Raonic fired 82 winners past the fourth seed to set up a second successive quarter-final at Melbourne Park.
Having lost to Djokovic a year ago, he will be favorite against French showman Gael Monfils who delighted fans with some spectacular dives as he beat Russian Andrey Kuznetsov 7-5 3-6 6-3 7-6(4) to reach the quarter-finals for the first time.
Raonic is on an eight-match winning streak since the start of the year, a run which included upsetting Roger Federer to win the Brisbane International, and he credits new coach Carlos Moya for giving him confidence to stray from the baseline.
"He's sort of organizing my strengths, my weapons and how to use them better," the 13th seed told reporters.
Chinese qualifier Zhang, on a fairytale run after snapping her streak of 14 first-round exits at grand slams, overhauled a hobbling Madison Keys 3-6 6-3 6-3 in the day's late match.
The 133rd-ranked 27-year-old struggled to put the ailing American down but eventually celebrated becoming the first qualifier to reach the last eight in Australia since Mexico's Angelica Gavaldon in 1990.
"I want to say bad luck to Madison for her injury. But I'm very lucky today," an elated Zhang told the crowd after tossing her racquet in the air in jubilation.
"I think one week ago people were thinking 15 times first round and that I would be going back to China."
After the stress of Nigel Sears' collapse at Rod Laver Arena on Saturday, Murray returned to the same venue to ease past world number 17 Tomic 6-4 6-4 7-6(4) and will battle hyper-fit Spaniard David Ferrer for a spot in the semi-finals.
Murray's Sydney-born compatriot Konta, granted British citizenship in 2012, continued her superb run, overhauling last year's semi-finalist Ekaterina Makarova 4-6 6-4 8-6 in a match lasting three hours and four minutes.
"Those four minutes count!" Konta said.
Twice champion and 14th seed Victoria Azarenka continued her ominous advance, beating Czech Barbora Strycova 6-2 6-4.
The former world number one has dropped only 11 games so far. "I played smart, I played aggressive and I took my opportunities. Can someone tell me if the Broncos won?" she asked the crowd at Rod Laver Arena, having spent the morning worrying about whether her favorite NFL team had reached the Super Bowl.
Azarenka next plays German seventh seed Angelique Kerber who she thrashed in the Brisbane International final.
Kerber reached her first Melbourne Park quarter-final with a 6-4 6-0 win over fellow German Annika Beck.
Monfils literally flew into the last eight where he will add some flair to proceedings.
One dive on the unforgiving Melbourne court against Kuznetsov left him with a cut hand. [L3N15925W]
"I just go for it. I'm just a competitor, I want to win every point and I think I can get it and I just fly," he said.
Eighth-seeeded veteran Ferrer booked his sixth quarter-final at Melbourne Park, thrashing American John Isner 6-4 6-4 7-5.
(Editing by Martyn Herman)