BEIJING, Aug. 10 (Xinhua) -- Top three seeds in the Olympic badminton women's doubles, all from China, checked into quarter-finals here on Sunday, despite tough challenges from their opponents.

    Defending Olympic champions Yang Wei and Zhang Jiewen were pitted against fledging Indonesian pair Liliyana Natsir and Vita Marissa, who cornered the champions in the semi-final of the Uber Cup in last June.

    The No.1 seeds started at a low engine in the first game of the first round, however, they geared up their speed and finally reversed the result at 21-19 and won the second game at 21-15 amid deafening chants for them from the enthusiastic spectators who "gave us motivation, not pressure," according to Zhang Jiewen.

    "It is a tough match," said Zhang Jiewen. "We are a little bit stiff on the court at first, as it is the Olympics, and it is 21-point scoring system."

    While No.2 seeds Du Jing and Yu Yang enjoyed a quick start in the first game against Ha Jung Eun and Kim Min Jung from South Korea, however, they were revenged by the Korean pair in the second game.

    After a seesawing third game, the rookie pair finally secured their victory at 21-11, 16-21 and 21-15.

    "There is no much difference between the Olympic Games and other tournaments," said Du Jing when asked of how she felt about her debut at the Olympic Games.

    It wasn't easy for No.3 seeds Wei Yili and Zhang Yawen to play against British veterans Gail Emms and Donna Kellogg either, who almost stole the first-game triumph from the Chinese pair, but finally lost it at 19-21.

    However, they failed to pick up their stamina in the second game, giving up resistance at 13-21.

    "I was a little bit stiff in the first game," said Zhang Yawen, who checked into the Olympics for the first time. "But in the second game, I felt much more relaxed and didn't leave the rivals any chance to win."