New York - Yanina Wickmayer Wednesday set up an all-teenaged women's semi-final at the top of the US Open draw as she defeated Kateryna Bondarenko 7-5, 6-4 in their quarter-final.

The 50th-ranked Belgian, 19, who has only advanced past the first round of a Grand Slam once before - this spring at Roland Garros 2009 - will play the winner from US 17-year-old Melanie Oudin and Danish ninth seed Caroline Wozniacki, 19.

Wickmayer achieved her unexpected placing in only her second main- draw appearance at Flushing Meadows and is poised for another possible breakthrough.

"I think I've worked so hard the last few years getting my physical and my mental in a good level," said the winner, who lost a grass-court final this summer in the Netherlands. "I think it's just all coming together this week.

"The last weeks I felt like it was going to come. I was really feeling well on the court. Everything was getting together. I've been feeling really strong, and mentally I've been always trying to stay calm and stay aggressive at the same time. I think that's one of the keys for me."

Wickmayer struck 31 winners and broke Bondarenko five times in a victory lasting an hour and three-quarters.

The victory was Wickmayer's 46th of the season against 20 defeats. dpa