SINGAPORE - China's Pan Zhanle said he was "not sure what happened" after crashing out in the heats of the 200m freestyle at swimming's world championships in Singapore on Monday.
Pan, the 100m freestyle Olympic champion and world record holder, finished only 22nd fastest in 1min 47.46sec to miss out on the top 16 who qualify for the semi-finals.
"I felt OK yesterday but today's swim felt completely different," said Pan, whose time was way outside his 200m best of 1:44.65.
"I'll have to keep working hard and make adjustments, I'm not sure what happened and I'm not happy with this time."
Romania's David Popovici, the 200m Olympic champion, cruised through fastest in 1:45.43 ahead of American Luke Hobson (1:45.61) and Britain's Matthew Richards (1:45.66).
Pan said it would not knock his confidence for the 100m.
"The 200m and 100m are two different events," he said.