DOHA, Dec. 11 (Xinhua) -- Top seed Lee Hyung Taik did not seem to be firing on all cylinders to beat Uzbekistan's Denis Istomin in a quarterfinal match here on Monday.

    He needed only one hour and 22 minutes to beat Istomin 6-1, 7-5.

    "I am very happy to get to the semifinals. I've played Istomin a few times in the past, and the second set was difficult because his serves and ground strokes were very good," said Lee, who was aiming to the top honour especially after Thai Paradorn Srichaphan, the defending champion, quit the men's singles competition citing an injury.

    While the second seed Lu Yeu Hsun from Chinese Taipei was stunned by Japanese Go Soeda 4-6, 6-2, 6-1.

    "I think he (Lu Yeu Hsun) just got tired. In the first set he was serving well but in the second set he started making mistakes," said Soeda.

    In the semifinals Lee will face Cecil Mamiit from the Philippines, who beat Wang Yeu Tzuoo of Chinese Taipei 2-6, 6-2, 6-2 and Soeda meets Danai Udomchoke from Thailand who beat Jun WoongSun of South Korea 7-6(4), 3-6, 6-3.