MELBOURNE - Kim Clijsters may have won four grand slams in a glittering career, but the Belgian, who took a step closer to defending her Australian Open title Friday, believes there is still room for improvement.

The 28-year-old beat long-time rival Daniela Hantuchova of Slovakia in straight sets in the third round on Friday, edging a close first set before running away with the second to win 6-3, 6-2 on the Hisense Arena.

It was her first match on Melbourne Park's secondary court since she had a meltdown against Nadia Petrova two years ago and lost 6-0, 6-1 in 52 minutes, her heaviest ever defeat at a grand slam.

"I wanted to play well, to really focus and not let that happen again," she said. "I think it made me focus a bit more."

Clijsters, who spent time away from the game to have her first child, intends to retire for good at the end of 2012, but the hungry player said she still wanted to improve during her final year on the tour.

"I still believe that I can improve. I would like to improve every day," she said.

"That's one of the main reasons why I decided to put Carl (Maes) on board (as coach) again.

"I have the feeling that I have been improving in a lot of different areas as well as emotionally, tactics-wise, physically, and confidence.

"I think those are a few of the things that I felt I needed to improve on."

"Look at (Rafael) Nadal, (Roger) Federer," she added. "You know, you can always improve. You can always become better. You can always work out harder in the gym and work out differently."

Clijsters will need to better Friday's effort if she wants to go much further in the tournament.

She was not at her best against Hantuchova, whom she last met in Brisbane two weeks ago when a hip injury forced her to withdraw from their semifinal.

The match in Melbourne was closer than the scoreline suggested, with Hantuchova missing a number of chances to put pressure on the defending champion with some simple mistakes.

The 11th-seeded Belgian broke Hantuchova five times in the match, but was broken twice herself as she made only 56 percent 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 in general, I still felt like I was hitting enough winners.

"I made the right decisions on important points at the important time and didn't come up with any unforced errors there, so that's obviously the most important thing."

Wozniacki shrugs off rankings scrap

World No 1 Caroline Wozniacki insisted on Friday she was not worried about holding onto her top ranking despite the strong possibility that she will lose it at the end of the Australian Open.

Wozniacki reached the fourth round of the Open on Friday with an impressive 6-2, 6-2 win over Romania's Monica Niculescu.

The 21-year-old Dane has been No 1 for 67 of the last 68 weeks, only relinquishing the position to Kim Clijsters for one week last February, but needs to reach the quarter-finals just to have a chance of staying on top.

Wozniacki is one of four players, along with Petra Kvitova, Victoria Azarenka and Maria Sharapova, who could finish the Australian Open at the top of the rankings list.

"To be honest, I just play," she said. "I want to try to do my best here. Whatever happens, happens.

"I've proven myself for the last two years. I've finished number one twice in a row. For me, the most important thing is to keep improving. If I do that, I know I can play at a very high level.

"If you win matches in tournaments, then the ranking will be there automatically."

Agence France-Presse