China was ensured of at least one Olympic badminton gold medal when both of its top-seeded pairs reached the mixed doubles final Thursday. Top-seeded Zhang Nan and Zhao Yunlei will face second-seeded Xu Chen and Ma Jin after both teams came back from losing the first game of their semifinals to make Friday's final. Zhang and Zhao, the world champions, won a thriller from Joachim Fischer and Christinna Pedersen of Denmark 17-21, 21-17, 21-19 in an hour and 21 minutes. Xu and Ma beat Tontowi Ahmad and Liliyana Natsir of Indonesia 21-23, 21-18, 21-13. Natsir won the mixed doubles silver medal in Beijing, and will play for bronze against the Danes. The results were welcomed by the Chinese, whose Olympics have been marred by the disqualification of one of their women's doubles teams, which intentionally lost a match to try to get a more favorable seeding. The defeat of Ahmad and Natsir meant Indonesia will not win badminton gold at an Olympics for the first time. (For more sports news and updates, follow Ahram Online Sports on Twitter at @AO Sports and on Facebook at AhramOnlineSports)