Sindhu, the reigning world champion, went down 21-19, 12-21, 17-21 in a match that lasted almost an hour. 

In the opening game, Tzu Ying started off brilliantly and took a healthy lead at the mid-game break. However, the Indian staged a brilliant turnaround as she came out with a spirited performance and went on the clinch the game 21-19 in 20 minutes. 

In the second game, the world number one, however, raced to a 6-0 lead against Sindhu. The Indian did try to stage a comeback but the Taiwanese was too good and won the game 21-12 to force the match into the decider. 

In the third and final game, the Rio Olympic silver medallist did show some fight but it wasn't  sufficient as Tzu Ying won the 21-17 to seal the match. 

The 25-year-old Indian will next face Ratchanok Intanon, who defeated her last week in a lop-sided Thailand Open quarter-final clash. 

Sindhu has to win at least two matches in the Round Robin stage to make it to the semi-finals. Pornpawee Chochuwong of Thailand is the fourth member of Group B. 

The World Tour Finals, offering total prize money of $ 1,500,000 this year, is played by the eight highest-ranked players in the rankings in each of the five events: men's and women's singles, men's and women's doubles, and mixed doubles. 

The eight entries are then divided into two groups of four. The group matches are played in a round-robin format, with the top two finishers in each group advancing to the semi-finals. 

Sindhu is the only Indian to win the tournament as she went all the way in 2018.