MELBOURNE World number one Jennifer Capriati's defense of her Australian Open title will face its stiffest test to date today when she plays Kim Clijsters in the semifinals.

Capriati has hardly put a foot wrong so far but will have to be at her best to beat Clijsters in a repeat of last year's French Open final.

Former world number one Martina Hingis also faces a tough job keeping alive her hopes of winning her first Grand Slam title in three years. She faces Monica Seles in today's other semifinal.

Capriati's match against Clijsters promises to be one of the highlights of the tournament if their last meeting is anything to go by.

That was in last year's French Open where Capriati eventually won 1-6 6-4 12-10 in one of the best women's finals in decades, reported Reuters.

"After the French Open we built up a very good relationship together and I've been practicing a lot with her," said Clijsters, Belgium's world number four.

"Now of course I would like to play her again and try to get revenge if that's possible."

Clijsters has been in ominous form over the past week and a half, winning all of her matches in straight sets, including a 6-2 6-3 demolition of her Fed Cup teammate and Wimbledon finalist Justine Henin in Wednesday's quarterfinals.