Unseeded Kim Clijsters's improbable charge into the US Open semifinals has surprised the Belgian as much as anyone.

Clijsters, who returned to the tour several weeks ago after two years on the sidelines, breezed by China's Li Na 6-2, 6-4 on Tuesday on Arthur Ashe Stadium.

"I never had that kind of mentality before the tournament knowing that I was going to get to a semifinal or final at the Grand Slams, obviously," said the 2005 Open champion.

But the former world No 1 is now in the last four, where she will face three-time champion Serena Williams.

Clijsters, who left the game to start a family, said her confidence grew during a round of 16 appearance in Toronto last month where she lost to world No 5 Jelena Jankovic.

"Something switched with me after Toronto where I felt like, 'Okay, I can compete with these girls.' That was obviously a big question in my mind," Clijsters said.

"Although I was hitting the balls really good in practise and I felt physically I was doing well, you still want to know what it's like to play against those girls and get a feel for how the level has changed, how girls are playing different tennis maybe these days.

"So I am surprised that I'm sitting here talking to you right now, but I'm very happy, and, you know, flattered that I get to do that."

The 26-year-old Clijsters dominated her match against the 19th-ranked Li and avenged a loss she suffered the last time they met in 2007.

Li, who had 41 unforced errors, won three successive games in the second set to take a 4-3 lead but Clijsters responded with a three-game streak of her own to close out the match.

"She's always been able to step it up at the grand slams," the Belgian said of Williams, her next opponent. "I've seen her play here and she has that face where she's like, 'I'm here to do business'.

"But that doesn't mean that you don't get chances when you get to play her. The one who keeps the unforced errors down I think is going to get through."

(Reuters via China Daily September 10, 2009)