Third seed Victoria Azarenka of Belarus beat Czech Iveta Benesova 6-2, 6-2 to became the first player to reach the Australian Open quarter-finals on Sunday.
Azarenka, seeking her first grand slam title, will now face Polish eighth seed Agnieszka Radwanska in the last eight.
Radwanska advanced in impressive fashion when she beat up-and-coming German Julia Goerges 6-1, 6-1.
The Pole broke Goerges at the first attempt and went on to secure a further five breaks against the faltering German. Radwanska will be looking to make her first grand slam semi-final appearance when she takes on Azarenka.
The Belarusian was quickly into her stride against the 46th-ranked Benesova, breaking twice in the first set.
She maintained her firm grip on the contest in the second set, again breaking twice to wrap up the match in 1hr 17mins.
The 22-year-old did not face any break points against her serve until the final game of the match, but managed to serve out for victory.
Azarenka, who is in contention to secure the number one ranking after the Australian Open, said she felt full of confidence after her win in Sydney earlier this month, which means she is still unbeaten this year.
"Of course I'd be a liar if I said I don't care about it but it's a little bit in the back of my mind," she said of her chances of reaching the top spot.
Azarenka's run to the quarter-finals equals her best result at the season's opening grand slam, which she achieved in 2010.
The Belarusian will try to go one better against a foe she knows very well who is also in the best form of her career.
"We've had so many great matches, long matches, long rallies. I'm sure it's going to happen again," Azarenka said.
"But I think she's improved tremendously since the end of last year. You could see the difference. She's become more aggressive. She's improved her serve."
Radwanska agreed there would not be any surprises when the two meet on Tuesday.
"I think when you play someone a couple times you already know what to expect," she said.
"Of course we're friends, but we are both professional, so when you go on court, we are just doing our best and everything to win the match. And of course after the match we shake hands and are friends again."
AFPTags: sport, australian-open, tennis, melbourne-3000, vic, australia First posted January 22, 2012 12:30:37