World No.6 Sindhu lost 13-21 21-18 19-21 to world No.42 Pai in a 74-minute women's singles match.
Fuzhou: World Champion PV Sindhu suffered a shock defeat to lower-ranked Pai Yu Po of Chinese Taipei in the opening round to be ousted from the USD 700,000 China Open here on Tuesday.
World No.6 Sindhu, who made early exits in China, Korea and Denmark, lost 13-21 21-18 19-21 to world No.42 Pai in a 74-minute women's singles match here.
However, Satwiksairaj Rankireddy and Ashwini Ponnappa, ranked 30th, beat Canada's Joshua Hurlburt-Yu and Josephine Wu 21-19 21-19 to make a positive start in the mixed doubles competition.
In men's singles, HS Prannoy, who has recently recovered from dengue, faltered in the opening round, losing 17-21 18-21 to Denmark's Rasmus Gemke.