American Marconi Wireless News - Olympic champ Pan crashes out again in second worlds flop

Pan, who stunned the world by winning gold in Paris in a new record time of 46.40sec a year ago, finished 10th in the semi-finals in Singapore, missing out on the eight-man final.

His time of 47.81 was a full second behind the fastest qualifier, American Jack Alexy.

"To put it plainly, I just wasn't in good shape today," said the 20-year-old Pan.

"I'll continue to work hard."

Pan also flopped in the 200m freestyle in Singapore, going out in the heats.

Australia's Kyle Chalmers, who qualified for the 100m final from the same semi-final as Pan, said his Chinese rival was "probably struggling a little bit".

"He said to me this morning after the heat, 'I am tired' after we touched the wall, so I'm assuming he's not at his best," said Chalmers.

"He had such a successful Olympic year last year. A lot of Australian Olympic athletes like myself have struggled the year after the Olympics, historically.

"I'm sure he's probably even more famous than I ever was in Australia."

Pan's win in Paris turned heads in the swimming world, with Australian Olympian-turned swimming coach Brett Hawke questioning its legitimacy.

Hawke, an Australian Olympic sprint freestyler himself who went on to mentor Brazil's Cesar Cielo, the first man to break 47 seconds, claimed the world record time was "not humanly possible".

P.Mathewson--AMWN