- Defending champion Kim Clijsters and Li Na will face each other at Australian Open
- The fourth-round clash will be a repeat of the 2011 final, which Clijsters won
- World No. 1 Caroline Wozniacki also advances into the round of 16
- Third seed Victoria Azarenka keeps alive her hopes of reaching top of tworld rankings
Defending champion Kim Clijsters will face Li Na for the first time since last year's Australian Open final after both women reached the last 16 of the tennis season's opening grand slam on Friday.
Former No. 1 Clijsters, seeded 11th after long injury absences last year, won 6-3 6-2 against Slovakian 20th seed Daniela Hantuchova.
Fifth seed Li, who lost to the Belgian in straight sets before becoming Asia's first major winner at the French Open, had even easier progress when opponent Anabel Medina Garrigues retired in the first set due to a injury.
The Spanish 26th seed, who had beaten China's world No. 6 in their previous four encounters, rolled her ankle at 2-0 down and had a long medical timeout before losing the next game and quitting in floods of tears.
"Last year in the final I think for me was a good match to remember," Li told reporters. "After that match I was feeling I really can win a grand slam.
"I think we play the same way, like playing against a mirror. What can I do? ... Only thing is I just try my best tennis on the court."
Four-time grand slam champion Clijsters felt there was still room for improvement in her game despite recording a third successive straight-sets win.
"I felt like I kind of just had to find my aggressive footwork and positioning on the court," the 28-year-old said. "But I was able to at the important points win those points and make the right decisions.
"Obviously at the end of the day, when you're not playing your best, what it comes down to is just trying to play the important points as well as possible. I was able to do that today."
Top seed Caroline Wozniacki will face either Clijsters or Li in the quarterfinals if she can get the better of Serbia's former world No. 1 Jelena Jankovic.
The Dane, seeking a first grand slam title and needing to reach the last eight to have a chance of staying top of the rankings, beat Romanian 31st seed Monica Niculescu 6-2 6-2.
"I want to try to do my best here," the 21-year-old said. "Whatever happens, happens. For me, the most important thing is to keep improving. If I do that, I know I can play on a very high level."
No. 13 Jankovic, a semifinalist in 2008, won 6-2 6-0 against 42nd-ranked American Christina McHale, who had reached the third round of the Australian Open for the first time in her career.
Third seed Victoria Azarenka kept alive her hopes of moving to world No. 1 with a 6-2 6-4 defeat of German Hobart International winner Mona Barthel.
The Belorussian will next play 46th-ranked Czech Iveta Benesova, who won 6-1 6-3 against Russia's Nina Bratchikova.
Polish eighth seed Agnieszka Radwanska beat Kazakhstan's world No. 57 Galina Voskoboeva 6-2 6-2 to set up a clash with Germany's rising star Julia Gorges, who is in the fourth round of a grand slam for the first time.
The 22nd seed came from behind to win 3-6 6-3 6-1 against 80th-ranked Romina Oprandi, who eliminated fellow Italian Francesca Schiavone earlier this week.