The 17-year-old Oudin had reached the quarterfinals by defeating Anastasia Pavlyuchenkova in the first round, then upsetting No. 4-seeded Elena Dementieva, No. 13-seeded Nadia Petrova and former No. 1-ranked Maria Sharapova.
Wozniacki will face Yanina Wickmayer in the semifinals. Wickmayer, of Belgium, beat Kateryna Bondarenko, of Ukraine, 7-5, 6-4 today.
On the men's side, fourth-seeded Novak Djokovic reached the men's semifinals for the third consecutive year, beating No. 10 Fernando Verdasco of Spain 7-6 (2), 1-6, 7-5, 6-2. The Serb lost to Roger Federer in the 2007 final and the 2008 semifinals.
He could meet Federer again in the semis this year. The top-ranked Swiss is set to play his quarterfinal match against Robin Soderling later tonight.