Switzerland's Viktor Roethlin underlined his Olympic credentials by powering to victory in the Tokyo Marathon in a championship best time yesterday.

Roethlin, bronze medallist at last year's world Championships in Osaka, set a new Tokyo record with a time of 2:07:23, almost a minute inside his personal best.

Japan's Arata Fujiwara was a distant runner-up in 2:08:40 with Kenyan Julius Gitahi third in 2:08:57.

Roethlin enhanced his status among the favourites for the Olympics in August, breaking away at the 35-kilometre mark to finish well clear of a high-quality field.

"It's unbelievable," the 33-year-old told reporters.

"It's a dream come true. To be third in Osaka and then come back to the country of marathon running and win in Tokyo... I have no words."

Roethlin smashed his previous personal best time by 57 seconds with a flawless run over a course Tokyo plans to use if chosen to host the 2016 Olympic Games.

"After this it all starts again for Beijing," said the European silver medallist. "I will have to be ready but after winning here I think I'm going in the right direction."

Some 33,000 runners entered the race, which began in the Shinjuku business district and snaked past several of the city's tourist spots, including the Imperial Palace, temples and the glitzy stores of Ginza's famous shopping area.

Fujiwara, whose legs began buckling at the 38km mark, collapsed with cramps at the finish line but his second place gave him a good chance of making Japan's team for Beijing.