Defending Australian Open women's champion Kim Clijsters made 18 unforced errors in a sometimes sloppy display but still advances to the fourth round, where she will meet China's Li Na.
Kim Clijsters far from perfect but makes Melbourne's fourth round
After Clijsters, the defending champion, reached the fourth round with a 6-3, 6-2 win over Slovakia's Daniela Hantuchova, Li went through when the Spaniard Anabel Medina Garrigues retired in tears after injuring her ankle.
Clijsters will need to improve on yesterday's effort if she wants to advance much farther in the tournament.
The match was closer than the score suggested, with Hantuchova squandering, through simple mistakes, several chances to apply pressure the 11th-seeded Belgian. Clijsters broke Hantuchova five times in the match, but was broken twice herself as she made only 56 per cent of her first serves.
Clijsters also made 18 unforced errors in a sometimes sloppy display but was rescued by her ability to smash winners from all over the court, 27 of them compared with 12 from Hantuchova.
"I think, in general, the type of player that I had in front of me who hits the ball very low over the net where you're going to have to step in, there's going to be a higher unforced-error count," Clijsters said.
"But … I still felt like I was hitting enough winners."
Li was leading 2-0 in the first set when Medina Garrigues agonisingly turned her right ankle during a baseline rally.
After a medical time-out she tried to continue but lost the next game and retired during the fourth.
The injury ensured Li's match with Clijsters, the first meeting between the two since last year's final, won by the Belgian in three sets.
Wozniacki cruised past Romania's Monica Niculescu 6-2, 6-2, but Azarenka was handed her first real test of the tournament before beating Germany's Mona Barthel 6-2, 6-4.
The world No 1, who could lose her grasp on the top ranking here, will take on the former world No 1 Jelena Jankovic, who easily beat the American Christina McHale 6-2, 6-0.