Osaka (Japan), Sep 4 (IANS): Two-time world champion Akane Yamaguchi from Japan overcame South Korea's An Se-Young in straight sets to win her third women's singles title at the Japan Open badminton tournament here on Sunday.

Yamaguchi, who defeated China's Olympic champion Chen Yufei to retain her world title last Sunday, breezed past a fatigued An Se-Young 21-9, 21-15 in just 38 minutes.

"We were both tired, but I knew I needed to take control of the game," the 25-year-old Yamaguchi said. "I knew I had to push myself to the limit and use the fans to move me."

The men's singles crown was also won by a Japanese shuttler. Kenta Nishimoto scored the biggest victory of his career with an upset victory over fourth seed Chou Tien Chen of Chinese Taipei 21-19, 23-21, 21-17.

China's lowly-ranked pair Liang Weikeng/Wang Chang, who started to play together four months ago, continued their giant-killing run by beating seventh seed Kim Astrup/Anders Skaarup Rasmussen of Denmark 21-18, 13-21, 21-17 to win their first title of any kind.

"This is the biggest tournament I have played in my career," Liang said. "I have never seen such a medal before."

An excited Wang said, "I wished to run a victory lap inside the gymnasium, but I was too tired to run."

Team China had a total of 29 players at the Japan Open but all their star players, including their Olympic and world champions, failed to reach the finals.

"Our goal is to break into the top 20 in the world rankings at the end of this year," said Wang. "So we can play the qualifying tournaments for the Paris Olympics."

Jeong Na-Eun/Kim Hye-Jeong beat Baek Ha-Na/Lee Yu-Lim 23-21, 28-26 in an all-South Korean women's doubles final.

The mixed doubles champion was won by Dechapol Puavaranukroh/Sapsiree Taerattanachai of Thailand, who ousted Japan's Yuta Watanabe/Arisa Higashino 16-21, 23-21, 21-18.