Australian star Ian Thorpe's much-anticipated comeback faced another setback on Saturday with a lacklustre performance on the first day of the World Cup short-course swimming championships in Tokyo.
The five-time Olympic champion, who quit the sport in 2006 aged 24, announced in February he was returning to competition.
But on Saturday, Thorpe clocked 49.45 seconds, finishing in 12th place among 50 swimmers in the morning heats and failing to qualify for the men's 100-metre freestyle final.
The final was won by fellow Australian Kyle Richardson in 47.31 seconds.
Thorpe refused to talk to reporters, saying he was in a poor physical condition. It was not immediately known whether the swimmer -- who also failed to shine at recent competitions in Beijing and Singapore -- would take part in Sunday's racing.
The day also held disappointment for two-time Olympic double gold medallist Kosuke Kitajima of Japan, who finished in fifth place in both the men's 50m and 200m breaststroke finals -- which were won respectively by Australia's Christian Sprenger in 26.54 seconds and Japan's Ryo Tateishi in 2:03.49.
"I'm far from on my best form. I didn't prepare for these races very well. I couldn't swim my best today," said Kitajima, 29, the winner of the 100m and 200m at the Athens and Beijing Olympics.
"I just tried to enjoy the races, I didn't have a target time. I'm not feeling well at all right now. What's lacking now is a strong feeling to swim well."
Japan collected eight gold medals on the competition's first day, while Australia netted four. South Korea won two titles, while China, New Zealand and Sweden each took one.
The 2009 world 100m long-course backstroke champion Junya Koga led a 1-2-3 finish by hosts Japan to win the men's 100m in 51.21 seconds.
World 200m long-course champion Takeshi Matsuda and Daiya Seto both set new Japanese records, winning the men's 200m butterfly in 1:49.50 and the men's 400m individual medley in 4:02.44 respectively.
Also helping the hosts to their medal tally were Takuro Fujii in the men's 100m individual medley, Ryo Takayasu in the 50m butterfly, Aya Terakawa in the women's 50m backstroke and Haruka Ueda in the 200m freestyle.
Robert Hurley won the men's 400m freestyle in 3:42.44 and Cate Campbell the women's 50m freestyle in 23.93 to join Richardson and Sprenger among the Australian winners.
Kim Hye-Jin and Choi Hye-Ra gave South Korea the women's 100m breaststroke and 200m individual medley titles, while China's Ren Luomeng won the women's 800m freestyle.
Therese Alshammar of Sweden won the women's 100m butterfly and Melissa Ingram of New Zealand emerged victorious in the women's 200m.