UPDATE 1-Tennis-Clijsters warms to task as Melbourne title beckons

* Belgian favourite made to work

* On course for first Melbourne title (Adds details, quotes)

By Alastair Himmer

MELBOURNE, Jan 26 (Reuters) - Chilly weather and low-flying planes failed to throw Kim Clijsters off course on Wednesday as the Belgian overcame Poland's Agnieszka Radwanska 6-3 7-6 to reach the Australian Open semi-finals.

Clijsters, a Melbourne finalist in 2004, underlined her billing as tournament favourite in a scrap against 12th seed Radwanska in unseasonably chilly conditions.

Roaring fly-overs from the Roulettes aerobatics display team over Rod Laver Arena to celebrate Australia Day did little to help the players in a quarter-final that rarely set pulses racing.

"It was a little scary," former world number one Clijsters said of the planes. "They seemed to be flying pretty low. They were loud.

"I just physically felt a little bit tired and heavy out there today."

Clijsters said she would not underestimate second seed Vera Zvonareva in the semi-finals, despite having thrashed the Russian 6-2 6-1 in last year's U.S. Open final.

"Hopefully I can bring my best tomorrow," said the three-times grand slam champion, who played with taping on her leg to protect a tight hamstring. "Everything has to be better.

"(Zvonareva) was really disappointed after I played her at the U.S. Open. But mentally as well she's improved.

"She used to really have moments where she could really be out of it sometimes. A lot of us players really enjoyed watching her sometimes go a little crazy out there," added Clijsters mischievously.

The Belgian traded breaks at the start with Radwanska in their quarter-final before taking the first set in 29 minutes.

Radwanska forced a tiebreak in the second, but Clijsters quickly snuffed out the danger, sealing it 7-4 with a bullet of a backhand the Pole could only flap wide off the line.

Clijsters, who committed an uncharacteristic 37 unforced errors, warned that world ranking would count for little when she and Zvonareva get down to business in the semi-finals.

"It's just a number," she said. "I just try to be the best Kim out there whenever I play, and it's not about numbers."

Radwanska complained the screeching planes had spoiled the occasion.

"I didn't really expect it," said the Pole after contesting, and losing, her fourth grand slam quarter-final. "It was pretty loud and not much fun. It was the same for Kim."

But the 21-year-old paid tribute to Clijsters.

"On the important points she didn't miss," said Radwanska. "I had a lot of chances but if you don't use them against the top players it's hard to come back."

(Editing by John O'Brien and Peter Rutherford; To query or comment on this story email sportsfeedback@thomsonreuters.com)

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