Chinese World champion Lin Dan was unhappy with the judges after being upset on home soil by South Korea's Park Sung-hwan in the China Masters first round in Guangzhou, local media reported on Thursday.
After winning the first set 21-19, Lin squandered two match points to lose the second 20-22, before Park sealed victory 21-17 in the third.
World number one Lin complained that line judges made several wrong calls in Park's favour.
"You all saw that this was not my home ground," the Beijing Youth Daily quoted Lin as saying.
"The line judges made a few decisions in my opponent's favour at crucial times," added Lin, who on Thursday's newspapers was dubbed "first-round Dan" rather than his usual "Super Dan".
Lin's loss capped a forgettable first day for China's men at the $250,000 tournament, with world number two doubles pair Fu Haifeng and Cai Yun losing to Abdul Latif Mod Zakry and Mohd Tazari Mohd Fairuzizuan of Malaysia.
The China Masters is the 11th round of the inaugural 12-stop Super Series circuit, which culminates in the Dec. 18-23 finals at a venue to be confirmed.