Guangzhou (China), Dec 12 (IANS): India's P.V. Sindhu on Wednesday beat world number two and defending champion Akane Yamaguchi of Japan 24-22, 21-15 in her opening match of the BWF World Tour Finals in Guangzhou.

World number six Sindhu, who lost last year's final to Yamaguchi in Dubai, saved two game points in the opening game and took the match in 55 minutes, reports Efe.

"It's important to start well in the group stage. I was nervous towards the end of the first game but once I won that game I played better," the 23-year-old Indian Olympic silver medallist said after the match, according to an official BWF report.

Sindhu trailed in both games but absorbed the pressure and fought back each time with a mix of aggression and patience.

Yamaguchi said she may have been too defensive against her opponent and would be hoping to repeat last year's performance, when she went on to win the tournament despite a first-round loss to Sindhu.

The top two players from the two groups will qualify for the semi-finals, after which a knockout draw will be held.

Sindhu and Yamaguchi have been clubbed together with world number one Tai Tzu Ying of Chinese Taipei and the United States' Beiwen Zhang in Group A.