(Reuters) - Dressed in black and oozing menace, Andy Murray extracted sweet revenge by felling Wimbledon nemesis Grigor Dimitrov in a late-night thriller as the old guard stood firm to march into the Australian Open quarter-finals on Sunday.
Former champions Rafa Nadal and Maria Sharapova sailed into the last eight but will share the limelight with Murray's next opponent Nick Kyrgios, a local gatecrasher who roared to a famous five-set victory over Roger Federer-slayer Andreas Seppi.
Dimitrov ended Murray's title defense at his home grand slam last season and the Rod Laver Arena crackled with tension as the pair slugged out a midnight classic.
Murray won 6-4 6-7(5) 6-3 7-5 and Dimitrov destroyed his racquet in disgust after blowing a 5-2 lead in the fourth set to allow the Briton to serve for the match.
The ending was cruel for Dimitrov but well-earned for Murray, as the Scot punched a cross-court forehand into the tape on match point, with the ball dropping over to send the Bulgarian out.
"I think I got quite lucky at the end, a few net cords went my way, that was the difference really," the Scot told reporters. "The momentum was switching both ways all the time."
Boasting a perfect 10-0 record over Australians, Murray will battle the home crowd as well as Kyrgios when the pair clash in two days' time.
Third seed Nadal continued his brilliant comeback from a 2014 season ravaged by injury and illness, drawing the sting from big-serving South African Kevin Anderson in a hard-fought first set before crushing him 7-5 6-1 6-4.
From writing himself off as a contender before the tournament, the Spaniard now faces Tomas Berdych for a place in the semi-finals, a man he has mastered in their last 18 matches.
"I am one of the eight. That's the most important thing," said Nadal.
"It would be very arrogant if I say I'm not at a very high percentage... I probably played my best match of the year."
Sharapova needed scarcely more than an hour to beat U.S. Open semi-finalist Peng Shuai.
The Russian's 6-3 6-0 romp set up a showdown with Canadian Eugenie Bouchard, a 6-1 5-7 6-2 winner over Romanian Irina-Camelia Begu.
Twenty-year-old Bouchard, long dubbed 'the next Sharapova', was overhauled by the Russian in three sets at the French Open semi-finals.
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Canada's first grand slam finalist Bouchard was the first into the last eight, giving herself a pep talk during a toilet break after suffering a mid-match meltdown.
"I gave myself a good long hard look in the mirror and I said, 'Genie, this is unacceptable' and I really kind of kicked myself in the butt a little bit," said Bouchard.
With the refurbished Margaret Court Arena promoted to the second showcourt, cheap ticket-holders have been given the run of Hisense Arena and the natives were restless as Kyrgios blew a 4-1 lead in the final set of his nerve-jangling 5-7 4-6 6-3 7-6(5) 8-6 win.
The moment of victory was delayed by a desperate line-call challenge by Seppi, but when finally confirmed, Kyrgios slumped to the ground in joyous exhaustion as most of the 10,000-strong crowd started early celebrations for Monday's "Australia Day" holiday.
The party might have been wilder but for seventh seed Berdych, who subjected local hope Bernard Tomic to a 6-2 7-6(3) 6-2 thrashing.
It was a banner day for Russia, however, with feisty left-hander Ekaterina Makarova booking her third Melbourne Park quarter-final in four years with a 6-3 6-2 thrashing of German Julia Goerges.
The much-improved 26-year-old should provide third seed Simona Halep with her first real test, the Romanian having enjoyed a worry-free 6-4 6-2 win over Belgian Yanina Wickmayer.
