|Thorpe defended his performance in Tokyo, saying he was 'comfortable' with his form so far [EPA]
Australian former star Ian Thorpe's Asia World Cup series ended with a whimper in the morning heats in Tokyo on Sunday when he finished 26th overall in the men's 100-metre butterfly.
The five-time Olympic gold medallist clocked 53.59 seconds, far behind top finisher Takeshi Matsuda of Japan in 51.39, failing to qualify for the final.
The Japanese duo of Ryo Takayasu and Kazuya Kaneda followed Matsuda in 51.40 and 51.63, respectively. Takayasu went on to claim the final in 50.52.
"This week has been challenging, but has been very good," said Thorpe.
"I wish I could have done it with no one watching but that's unfortunately not the case. I am very comfortable with where I'm at."
Out of shape
On Saturday, Thorpe also failed to qualify for the final of the men's 100m freestyle after finishing 12th with 49.45. He then pulled out of the 100m individual medley, citing a poor physical condition.
Thorpe's exit marked a disappointing return to action for the former Olympic champion ahead of Australia's Olympic trials in March, where he will bid to qualify for London 2012. He had quit the sport in 2006 aged 24, but returned to competition this year.
In the finals, hosts Japan - who won eight out of 17 titles on Saturday - added nine gold medals, while Australia took three to add to Saturday's four.
Two-time Olympic double gold medallist Kosuke Kitajima, who was fifth in the men's 50m and 200m breaststroke, finally won a medal when he finished third in the 100m in 58.36 seconds, behind fellow Japanese Ryo Tateishi and Australia's Christian Sprenger.
"I want to win at the qualifying races for the Olympics in April," said the 29-year-old from Tokyo.
"It will be tense. But you will become tense only once in four years. I'll just try to work hard," he said.
Other Japanese men's winners were former world champion Junya Koga in the 50m backstroke and Kosuke Hagino, who set a new national record of 1:53.67 to win the 200m individual medley.
They were joined by Yohei Takiguchi, who triumphed in the 1,500m freestyle, and Kenta Ito in the 50m freestyle.
Among the women who triumphed were world long-course silver medallist Aya Terakawa in the 100m backstroke, Miho Takahashi in the 400m individual medley, and Rie Kaneto in the 200m breaststroke.
The Australian victories came from the women's side, with Cate Campbell winning the 100m freestyle, Blair Evans the 400m freestyle, and Leiston Pickett the 50m breaststroke.
In other finals, world record holder Therese Alshammar of Sweden won the 50m butterfly, China's Zhao Jing took the 100m individual medley and South Korea's Choi Hye-Ra added the 200m butterfly to her 200m individual medley title.
In the men's events, South Africa and Colombia claimed their countries' first golds of the week, with Chad le Clos taking the 200m freestyle and Omar Pinzon the 200m backstroke.