'Miscalculation' costs Peirsol shot at 100m backstroke crown

Aaron Peirsol's shot at a fourth straight 100m backstroke world title evaporated yesterday with a 'huge miscalculation' that cost him a spot in the World Championship final.

Less than three weeks after he set the 100m backstroke world record with a time of 51.94 at the US trials, Peirsol failed to reach the World Championship final.

The defeat means he won't get a chance to add to the 100m titles he won in 2003, 2005 and 2007, which go with his Olympic golds from 2004 and 2008.

"That was a huge miscalculation," Peirsol said. "I thought I was in a much better place in that race than I was."

Peirsol finished fourth in his heat, won by Aschwin Wildeboer Faber, a Spaniard who had seized the 100m back world mark for a week in July before Peirsol grabbed it back.

"I thought I was right next to Aschwin, I didn't know I was half a second behind," said Peirsol. "It was very strange to see that time. Usually I'm not that bad (at judging his pace)."

Peirsol's time left him ninth-fastest overall in the semis and out of today's final.

Japan's Junya Koga was the fastest qualifier, winning the first semi-final in 52.39.

Peirsol, whose part-polyurethane Arena suit is among the new-generation costumes causing a storm in swimming this year, said his failure wasn't due to a lesser swimmer getting a boost from a fast suit.

"That was my own fault," he said. "We're all wearing suits."

Known for liking to keep something in reserve for the final, Peirsol said it wasn't that he held too much back, but simply that he didn't know where he was.

"I wasn't completely reserving there, I just thought I was in a place that I wasnt in. In backstroke you're looking straight up, you don't see much, you just have to go by feel.

"I felt great this morning, I didn't feel bad tonight. There's obviously a few things that I could have done better but that's a very fast field."

American Matt Grevers, who booked his place in the final with the fifth-fastest time overall, was astonished that he would be facing Peirsol.

"It's so hard to process that fact," he said. "I have no idea what happened with him. I know he likes saving up and make sure he has something for the final. Maybe he just saved a little too much and it was too little too late.

Grevers said the tumbling times in the stroke left no margin for any error.

"It's incredible how much faster backstroke's become. Last year the world record was 52.9 but now you need 52.9 just to make the final.

Peirsol still has the 200m backstroke remaining here. He made his first international splash at the longer distance, but settled for silver in the 200m at the Beijing Games.

He showed he was ready to reassert himself over 200m with a world record at the US trials this month.

"I'm going to have to put this one behind me and move on and prepare for the 200m," Peirsol said.