Eighteen-year-old Bilqis Prasista shocked the badminton world after beating world No. 1 Akane Yamaguchi at the Thomas and Uber Cup on Wednesday.
Yamaguchi suffered a 21-19, 21-19 defeat in 35 minutes at the hand of the Indonesian rookie, who is ranked more than 300 places below the world champion.
In the team event at Bangkok's Impact Arena, however, Japan roared back to beat the Indonesians 4-1 and top Group A.
Both teams have qualified for the quarterfinals of the women's Uber Cup.
"It's unbelievable. I could never imagine beating Akane Yamaguchi," Prasista, 333rd in the world rankings, said.
"I just wanted to make her run and chase the shuttle so it was no fun for her. That was the key."
The teenager made her mark early, leaving Yamaguchi scoreless as she jumped into a four-point lead in the first game.
Yamaguchi briefly recovered but came unstuck in the face of lethal net shots and smashes from her gutsy opponent.
Yamaguchi grabbed an early six-point lead in the second game before Prasista leveled the scores with a run of points, then inched to match point and a surprise victory.
It was a hat trick of wins for Prasista, who has also beaten German Florentine Schoeffski and France's Yaelle Hoyaux recently.
A disappointed Yamaguchi said the drift in the arena had made it difficult to control the shuttlecock.
"I couldn't control the game," the 24-year-old told reporters.
Elsewhere, South Korea thrashed India 5-0 to top Group D with An Se-young too good for P. V. Sindhu.
The world No. 4 claimed victory in 42 minutes, 21-15, 21-14, over the seventh-ranked Sindhu.
The Koreans and India are also both in the last eight of the competition.
