Jiang Yanjiao of China hits a return against Petya Nedelcheva of Bulgaria in their women's singles match at the China Open badminton tournament in Shanghai November 23, 2011. [Photo/Agencies]

Three-time China Open champion Jiang Yanjiao suffered a shock first-round exit after losing 21-15, 19-21 and 15-21 to unseeded Bulgarian Petya Nedelcheva on Wednesday.

"My neck was injured in October's Denmark Open, so I couldn't keep systematic training recently," said the 25-year-old Jiang, who won the China Open women's singles title between 2008 and 2010.

"So it's a pity that I missed the chance to win for the fourth time."

Other high-profile opening round losers include German champion Juliane Schenk, Swiss Open winner Saina Nehwal of Indonesia and Cheng Shao Chieh of Chinese Taipei.

Cheng blamed poor sleep for her bad performance.

"There is no excuse when you lost the game, but perhaps it's related to the fact that I didn't have a good rest last night," said Cheng after her 12-21 and 11-21 defeat against Chinese qualifier Liu Xin.

Schenk smashed her racquet and then sat angrily on the floor in the middle of the deciding third set in a protest against the linesman's judgement. Yip Pui Yin of Hong Kong, China saw off Schenk 21-18, 19-21 and 25-23.

In contrast, big names in the men's singles all advanced to the second round.

Grand slam winner Lin Dan of China reached the last 16 with a 21-10, 21-18 victory against Yan Kit Chan of Hong Kong, China.

"It's just my first day in Shanghai and I just came back after the Hong Kong Open, so it's normal that I didn't hit the best form," said Lin.

Former Olympic champion Taufik Hidayat looked exhausted after defeating Chinese qualifier Lv Yi at 21-17, 18-21 and 22-20 in a one-hour 24-mintue first-round match.

"First set is OK but second set I always missed. I played too slow and my concerntration was loose," said Taufik.

Rumors said that Taufik Hidayat had struck a secret deal with Peter Hoeg Gade that they will work together to prevent China from earning three Olympic berths in the men's singles discipline.

World No. 4 Peter Hoeg Gade has already vowed to avoid Chen Jin from leapfrogging him in the world rankings to enable China to have three full Olympic spots.

Chen currently stands in the fifth placing with compatriot Chen Long and Lin Dan ranking second and third, behind Lee Chong Wei of Malaysia.

According to the World Badminton Federation's rules, a country can field three players in men's singles at the Olympics only when it has three shuttlers ranked in the world top four.

"It's Peter Gade and me (who created the idea to set up the alliance against China). Still have time till april," said Taufik.

In mixed doubles, world championship runners-up Imogen Bankier/Chris Adcock were stunned by Malaysian duo Peng Soon Chan/Liu Ying Goh 17-21 and 16-21.

Also out were the sixth seeded Indonesians Mohammad Ahsan/Bona Septano as they went down 15-21 and 18-21 to Russian Open winners Naoki Kawamae/Shoji Sato of Japan in the men's doubles.

The China Open is the last BWF Superseries Premier stop ahead of the Superseries Finals. Sharing the same score system with the Superseries Finals, the China Open offers 11,000 points for the champions and 9,350 for the runners-up.