Roundup: Nadal, Dimitrov, Wozniacki hold strong on day seven of the Australian Open.

MELBOURNE, Jan. 21 (Xinhua) -- Although it was far from easy, all the big names made it through to the quarterfinals on Sunday, with day seven action providing some great contests for the 63,000 fans in attendance at the Australian Open.

With a final score of 6-3, 6-7 (4-7), 6-3, 6-3, you might think that world number one Rafael Nadal had a comfortable 4-set victory over Argentinian Diego Schwartzman, however the Spaniard was pushed to the limit during the match and had to fight hard for every game.

In the end, the precision of the 16-time Grand Slam winner, was enough to get Nadal into the remaining eight.

"He is a great player in all aspects and he was serving well," Nadal said in praise of Schwartzman.

"This was the first big match I have played in 2018 and I was able to fight until the end."

"A match like this probably helps because it builds confidence in knowing that I can resist almost four hours on court playing at a good intensity."

It was a similar story for world number three Grigor Dimitrov, when he faced home crowd favourite, Nick Kyrgios.

But the gripping, nail biting battle, was made even more tense when officials controversially called the Australian for several foot faults.

Eventually however, the Bulgarian was able to survive the power serve of Kyrgios and take the victory 7-6 (7-3), 7-6 (7-4), 4-6, 7-6 (7-3).

In the other matches, 6th seed Marin Cilic got past Pablo Carreno Busta in four sets and England's Kyle Edmund continued his dream run at the tournament by overcoming Andrea Seppi.

While in the women's bracket, world number two Caroline Wozniacki cruised her way into the quarterfinals with a straight sets win over Magdalena Rybarikova, world number four Elina Svitolina thrashed Denisa Allertova, Belgium's Elise Mertens got the better of Petra Martic and Carla Suarez Navarro edged out Anett Kontaveit in a three-set thriller.

Despite all the action of day seven, Chinese Taipei's Hsieh Su-Wei became one of the biggest talking points, when she teamed up with China's Peng Shuai in the women's doubles less than 24 hours before one of the biggest matches of her singles career against Germany's Angelique Kerber.

The duo eased their way past Raquel Atawo and Anna-Lena Groenefeld and will now move into the quarterfinals. Enditem