The defending champion was beaten 10-21, 21-17, 16-21 in the second round of the BWF World Tour Super 300 event at the Indoor Stadium Huamark.

Fitriani's reward for her stunning victory is a quarter-final meeting with Singapore's Yeo Jia Min, who defeated Germany’s Yvonne Li 21-6, 21-18.

At number three, Canada's Michelle Li is now the highest-seeded player remaining in the women's singles draw.

She overcame Japan's Ayumi Mine 21-6, 13-21, 21-10 to book her spot in the last eight.

There were also surprise exits today for fourth seed Cai Yanyan of China and seventh seed Cheung Ngan Yi of Hong Kong.

Cai was beaten 17-21, 17-21 by Japan's Saena Kawakami, while Cheung fell to a 21-12, 13-21, 20-22 defeat at the hands of compatriot Deng Joy Xuan, who will be Li's next opponent.

In the men's singles event, top seed Lin Dan of China remains on course for glory after overcoming Hong Kong's Lee Cheuk Yiu 21-19, 15-21, 22-20 in round two.

Standing between the two-time Olympic gold medallist and a place in the semi-finals is Malaysia's Cheam June Wei, who beat home favourite Pannawit Thongnuam 14-21, 21-17, 21-16.

Among the other players through to the quarter-finals are sixth seed Wang Tzu Wei of Chinese Taipei and seventh seed Brice Leverdez of France.

Wang defeated France's Lucas Corvée 21-17, 13-21, 21-15, while Leverdez overcame India's Subhankar Dey 21-19, 21-10.

Competition is scheduled to continue tomorrow. 

The winners will receive $150,000 (£117,000/€130,000) of prize money.

Action will run until the finals on January 13.