Ai Shibata, Olympic 800m freestyle champion and 2007 world bronze medallist in the 400m will not race over eight lengths in Beijing after winning at trials in Tokyo's Tatsumi International Pool but falling shy of her target time.

Shibata stopped the clock at 4:10.38, well down on the 4:08.43 target, with Yurie Yano second in 4:11.56 and Chika Yonenaga third in 4:11.76.

'I have no words to say at this moment,' a shell-shocked Shibata told Kyodo. 'We knew we would have these championships beforehand, so I have no excuse that I'm not in my best form. I must refresh myself and try to do my best to cut the qualifying time in the 800 metres at any cost.'

The trials end on Sunday after six days of racing. First on the team are Saori Haruguchi and Maiko Fujino. Haruguchi raced 4:38.94 to beat four-time defending national champion Fujino, on 4:40.14, ahead of Izumi Kato, on 4:41.68.

In the 400m freestyle, Takeshi Matsuda clocked his best time since 2005 in the 400m freestylefor a fifth straight national title in 3:47.36, just 0.08sec outside his pb. Shogo Hihara took the second berth with a 3:51.13, ahead of Shou Uchida, on 3:51.93.

Takahiro Mori won the 400m medley in 4:17.34, ahead of Hidemasa Sano, on 4:17.81, but their times will not take them to Beijing.

Kosuke Kitajima, Olympic 100m and 200m breaststroke champion, had a fine start to his campaign, clocking 59.87 and 59.66 in the heats and semis, respectively, of the 100m. Best through to the final of the 100m backstroke was Tomomi Morita, on 54.48.