MELBOURNE (AFP) - Rafael Nadal battled through a huge test to make his 10th Australian Open quarter-final on Sunday, as a ruthless Caroline Wozniacki kicked into full gear to book a date with Carla Suarez Navarro.
On an overcast and muggy day at Melbourne Park, the Spanish world No. 1 was up against his most dangerous opponent yet in pocket-rocket Diego Schwartzman, one of the smallest men on tour.
The Argentinian 24th seed endeared with his astonishingly powerful groundstrokes before Nadal prevailed 6-3, 6-7 (4-7), 6-3, 6-3 in almost four hours on Rod Laver Arena.
Late at night, Bulgaria's world No. 3 Grigor Dimitrov won a gripping four-setter to knock Australia's big hope Nick Kyrgios out.
Dimitrov downed the maturing 22-year-old 17th seed 7-6 (7-3), 7-6 (7-4), 4-6, 7-6 (7-4) and will face Britain's Kyle Edmund in the quarter-finals on Tuesday.
Edmund reached his first Grand Slam quarter-final with a 6-7 (4-7), 7-5, 6-2, 6-3 win over Italy's Andreas Seppi.
Nadal's victory kept alive his push for a 17th Grand Slam title and also ensured that he will remain top when the new rankings come out after the tournament ends.
"It was a great battle," said Nadal, who is chasing his second Melbourne title after beating Roger Federer in the 2009 final. "Of course, I feel little bit tired, but I was able to keep fighting until the end."
He will play sixth seed Marin Cilic for a place in the semi-finals after the Croat beat Spanish 10th seed Pablo Correna Busta 6-7 (2-7), 6-3, 7-6 (7-0), 7-6 (7-3).
The win was Cilic's 100th at a Grand Slam event.
"I have played great tennis from the first round against tough opponents and now I am really looking to the next match, it will be definitely be a big challenge," he said of the Nadal clash.
Ordinarily Nadal, as the top seed, would have top billing on Rod Laver in the evening, but not with local star Kyrgios in action.
World No. 2 Wozniacki turned on the style in her match to take another step towards a maiden Grand Slam title.
The assured Wozniacki, a semi-finalist in 2011 who has never quite lived up to the hype in the majors, annihilated 19th-seeded Magdalena Rybarikova 6-3, 6-0 in her most impressive performance to date.
"She really mixes up the pace, I just tried to calm down, get my returns in and wait for the opportunities to attack," she said after crushing the Slovak, who made the semi-finals at Wimbledon last year.
"I think you can tell my confidence is pretty good at the moment."
Her easy passage sets up a last-eight clash with gritty Spaniard Suarez Navarro, who battled back from a set and 1-4 down to shatter the hopes of 32nd seed Anett Kontaviet.
The Estonian had been bubbling with confidence after dispatching French Open champion Jelena Ostapenko in the third round, but nerves got the better of her.
The Spaniard, who has made the quarter-finals in Melbourne twice before, most recently in 2016, credited her fightback with a conscious decision to be more aggressive.
"My team all the time they say (to) me, play aggressive, play aggressive. That's I think what I did," said Suarez Navarro, one of the few who still uses a one-handed backhand.
Looking ahead to Wozniacki, she added: "I know how she plays. I know how tough she is. It will be a really interesting match."
The 37th-ranked Elise Mertens also made the last eight, becoming the first Belgian since Kim Clijsters in 2012 to get so far in Australia.
She posted a straight-sets win over Croat Petra Martic and will now play fourth seed Elina Svitolina, who galloped into the last eight with a late night 6-3, 6-0 demolition of Czech qualifier Denisa Allertova.
The Ukrainian sprinted through the match that did not start until 11.56pm in 57 minutes.
Mertens is a form player after winning the lead-up Hobart International, while Svitolina was the champion in Brisbane.