Incheon, Sep 25 (IANS): Ace Indian shuttler P.V. Sindhu on Wednesday crashed out of the Korea Open Super 500 tournament after suffering a shocking first-round loss to Zhang Beiwen of the US.

Fifth-seeded Sindhu, who became the first Indian to win Badminton World Championships gold last month, squandered a first-game advantage and went down 21-7, 22-24, 15-21 by World No. 10 Beiwen in a contest that lasted for almost an hour.

It was a tough loss for the reigning world champion as she had a match point in the second game. But the American hung in their and closed out the match comfortably eventually. With the win, Beiwen snapped a three-match losing streak against the Indian.

This was a second successive early exit for Sindhu. The 24-year-old had crashed out of the China Open World Tour Super 1000 badminton tournament as she went down fighting to Thailand's Pornpawee Chochuwong last week.

Earlier in the day, B. Sai Praneeth also made an early exit in men's singles event after he was forced to retire midway in his first-round match against Anders Antonsen of Denmark.

Praneeth had lost the first game 9-21 and was trailing 7-11 in the second when he chose to retire because of injury and thus send Antonsen through to the round of 16.