SHANGHAI — India's P.V. Sindhu pulled off a shock at the badminton World Tour Finals on Thursday as she fought back to defeat top-ranked Tai Tzu-ying for the first time in over two years.

Sindhu sank to her knees at the end of an exhausting 14-21, 21-16, 21-18 victory over the Taiwanese in 62 enthralling minutes in the southern Chinese city of Guangzhou.

The 23-year-old, a silver medalist at the Rio Olympics in 2016, faces Zhang Beiwen of the United States on Friday looking to make it three wins out of three in Group A of the $1.5 million end-of-year showpiece.

"Each point was hard fought," said a relieved Sindhu, ranked sixth in the world. "There were long rallies with good strokes. She was very deceptive and I had to be ready for her strokes.

"Even though I was trailing in the third game I didn't lose hope and I kept fighting."

It was a disappointing day for Taiwan as men's world No. 3 Chou Tien-chen also lost. Chou was on the end of an 18-21, 21-11, 21-14 defeat to South Korea's buoyant Son Wan-ho.

There was no such trouble for men's No. 1 and world champion Kento Momota of Japan. He is in ominous form as he looks to put the seal on a breakthrough year and swatted aside Thailand's Kantaphon Wangcharoen 21-15, 21-7 for a second win in a row.

China's Shi Yuqi, one of the main threats to red-hot Momota in the men's draw, dismissed Anthony Sinisuka Ginting of Indonesia, 21-8, 21-19 in 37 minutes. — AFP