2009
Lee Yong-dae started a bright year when he and Jung Jae-sung won the Malaysia Super Series. In Korea Super Series, Lee won the mixed doubles title with Lee Hyo-jung, while he and Jung only became the finalists. However, as Jung had to join the military service for two months, Lee paired with Shin Baek-cheol and claimed the German Open title. In the Swiss Open Super Series, Lee Yong-dae and Lee Hyo-jung reached the mixed doubles final but failed to capture the trophy as they lost to China's Zheng Bo and Ma Jin. A month later, they subdued teammates Yoo Yeon-seong and Kim Min-jung to clinch the Asian Badminton Championship title.
In the Sudirman Cup on May 10–17, Lee Yong-dae brought South Korea to the final to meet defending champion China. Lee always won in both the men's doubles and mixed doubles events. However, in the final, he and Lee Hyo-jung bowed to Zheng Bo and Yu Yang, while a few hours later he and Jung Jae-sung also surrendered to Cai Yun and Fu Haifeng. China then won the cup for the consecutive third time 3–0.
In June, Lee Yong-dae played in the Singapore Open Super Series, but he did not win any title. In Indonesia, a week later, nevertheless, he reached both the finals of men's doubles and mixed doubles event. Again, he and Lee Hyo-jung were defeated by Zheng Bo and Ma Jin, the Chinese pair who beat them in Singapore semi-final. Happily, he took the men's doubles title with Jung Jae-sung, conquering China's top pair Cai Yun and Fu Haifeng.
In August, Lee Yong-dae participated in the BWF World Championships in Hyderabad, India. Unfortunately, in the mixed event, he and Lee Hyo-jung, seeded first, lost to Thomas Laybourn and Kamilla Rytter Juhl of Denmark, who later became the champions. He had a better run with Jung Jae-sung in the men's doubles, reaching the final. They met Cai and Fu again, and this time, they lost.
In November, after a two-month absence due to injury, Lee Yong-dae returned to play in Hong Kong Open Super Series. Though he and Lee Hyo-jung lost in the first round, he fared better in the men's doubles with Jung Jae-sung. In the final, they defeated Lars Paaske and Jonas Rasmussen of Denmark.
Only a week later, Lee successfully defended his two titles in China Open Super Series. He and Lee Hyo-jung beat Zheng Bo and Ma Jin in the mixed doubles final. With Jung, he defeated Koo Kien Keat and Tan Boon Heong in men's doubles final.
In December, Lee and Jung participated in Super Series Finals in Johor Bahru, Malaysia. Unbelievably, they did not drop a single set from the group stage to the final. In the final, they outclassed Denmark's Mathias Boe and Carsten Mogensen, whom they had subdued in the group stage.
Read more about this topic: Lee Yong-dae, Career