DOHA (AFP) - Australian Open champion Maria Sharapova maintained her unbeaten record in 2008 as she thundered her way to the semi-finals of the Qatar Open with a victory in less than an hour on Friday.

The strident brevity of Sharapova's 6-1, 6-0 win over Caroline Wozniacki, a promising 17-year-old Dane, suggested she is unofficial favourite for her second title of the year as well provided her with her 12th successive victory in all competitions.

"It was a pretty solid performance apart from one game in the second set," said Sharapova.

"I felt pretty comfortable from the beginning. I was aggressive. I served and returned pretty well and felt pretty good."

Sharapova had the physical strength and the self-confidence not only to rush and harass her less powerful opponent, but also to hit through the desert wind which, though less fierce than during the previous two days, remained a constant annoyance.

She was helped by an error-spoilt start from her young opponent, enabling her to open up and take a few more risks quite early on.

When this too succeeded Sharapova was able to conduct the match at a bullying pace, hurrying between points and games to maintain the steamrollering effect.

Wozniacki received plenty of demonstrative advice during the interval between sets from her father-coach Piotr, a former professional footballer in Poland.

But though this may have helped her to hold serve in the opening game of the second set, she was unable to find much consistency, and, despite having changed to a racket with a different tension, was quickly under pressure again.

"I had to treat her with respect, because she had nothing to lose out there," added Sharapova.

"She's in a quarter-final of a tier one tournament against one of the top players, so for her it's about taking experience and playing freely - which is sometimes dangerous."

Sharapova now plays Agnieszka Radwanska, the elder of two rising sisters, the first Polish woman ever to make the world's top 20, and someone who could perhaps produce that danger.

Sharapova has plenty of motivation for victory as it was the Pole who knocked her out of the US Open last year.

"I don't like losing to an opponent twice in a row, so I am quite excited about getting an opportunity to play her again and give myself a chance to beat her," said the Russian.

Radwanska achieved her first Grand Slam quarter-final in Australia last month and has now reached her first WTA Tour semi-final with a three-hour 4-6, 7-6 (7/1), 6-4 win, having been behind in all three sets against another 18-year-old, Dominika Cibulkova of Slovakia.

"It is tough to play, and tough to serve and there were so many breaks," Radwanska said.

"That's one reason why it lasted so long (three hours). But anyway I will be ready tomorrow."

Earlier another Russian, Vera Zvonareva, an unseeded former top ten player, reached a semi-final for the second time this year, overcoming Sybille Bammer, the 15th seeded Austrian.

Bammer, the only mother playing regularly at the top level of the game, upset Svetlana Kuznetsova, the second-seeded former US Open champion, in a ferocious gale on Thursday but this time fell away tiredly to a 2-6, 6-2, 6-0 defeat.