Newly-crowned world number one Kim Clijsters feels she is ready to win her first grand slam title at the US Open.

"It motivates me very much," Clijsters told Reuters after becoming the first Belgian to claim the top ranking in tennis.

By ousting US Open champion Serena Williams - sidelined by a knee surgery - from the top spot on Monday, Clijsters became the first player to lead the rankings without winning a Grand Slam since WTA rankings were introduced in 1975.

"It will be tough because without Serena playing, there will be a lot players who think they have a bigger chance to win. But I like the challenge," said Clijsters.

Having achieved one of her goals for the year, Clijsters will not only be aiming for her first Grand Slam title but also to exact revenge from her compatriot Justine Henin-Hardenne at the US Open, which starts on August 25 in New York.

In June, Henin-Hardenne defeated Clijsters in the French Open final to become the first Grand Slam winner from Belgium.

But more recently the duo have been involved in a war of words after Henin-Hardenne beat Clijsters in a controversial final at the Acura Classic earlier in August.

Clijsters accused her rival of using an injury timeout at the end of the first set to regroup.

TOOK CONTROL

Henin-Hardenne, who had a blister on her foot treated during the break, took control of the match upon resumption, leaving a frustrated Clijsters fuming after her 3-6, 6-2, 6-3 defeat.

The world number three denied that she had made unfair use of the injury timeout, saying Clijsters was just upset because she lost the final.

"She's (Henin) the main challenger but there are other players who would like to get a win there too," Clijsters said.

"If I'm going to challenge her, it's going to be in the semis or final and I have to get there first. But if I play her, I'm definitely looking forward to revenge."

Referring to her dispute with Henin-Hardenne, she added: "I didn't mean anything bad by it, just to say that the blisters didn't seem to influence her movement in the second and third sets.

"I've never said Justine wasn't allowed to take it (the injury break)."

Clijsters is also looking forward to being the sport's leading lady.

"I always believed in promoting tennis and I've been pretty good about it, but now maybe I'll be more busy," she said.

"It's fine because that's what comes with being number one.

"It's nice to be in the position where you can have more to say and change things. Maybe now people will listen to me more," she said.