Reigning world champion PV Sindhu kept India's hopes of winning a first-ever Olympic gold in badminton alive as she reached the semifinals of women's singles with a fighting straight-game win over world no 5 Japanese Akane Yamaguchi on Friday.

The 26-year-old Indian, who won a silver in the 2016 Rio Olympics, defended brilliantly and rode on her attack to outclass the fourth seeded Yamaguchi 21-13 22-20 in a 56-minute quarterfinal clash at the Musashino Forest Plaza.

She will next face the winner of the other quarterfinal between Thailand's Ratchanok Inthanon and Chinese Taipei's Tai Tzu Ying. The sixth seeded Indian came into the match with a 11-7 head-to-head count against the Japanese, whom she had last beaten at the All England Championship in March this year.

On Thursday, Sindhu had notched up a straight-game triumph over Denmark's Mia Blichfeldt, 13th seed, in the pre-quarterfinals.

She was the lone Indian in fray in badminton after men's singles player B Sai Praneeth and men's doubles pair of Chirag Shetty and Satwiksairaj Rankireddy failed to qualify for the knockout stage.

(With PTI inputs)