Aaron Peirsol reclaimed the 200m backstroke world title here Friday, his world record-smashing swim easing the memory of his failure to reach the 100m backstroke final.

Peirsol's time of 1min 51.92sec obliterated his own world record of 1:53.08 that he set at the US championships in Indianapolis on July 11.

Japan's Ryosuke Irie was second in 1:52.51, and 2007 world champion Ryan Lochte of the United States was third in 1:53.82.

Although Peirsol came into the race as the world record-holder, Irie had actually notched the fastest time ever swum with a 1:52.86 in Canberra this year. It wasn't ratified as a record because he wore an unapproved suit.

Peirsol simply skipped over the entire 1:52s en route to reclaiming the world title he lost to Lochte in Melbourne in 2007.

He admitted that the time owed something to his polyurethane Arena X-Glide swimsuit, one of the breed that have wreaked havoc on the record book at these World Championships.

"My 200, I've been struggling to get faster for a few years now and kind of when it rains it pours," Peirsol said.

"You've got to put some of it up to the suits, I don't know how I can relate to what I wore tonight versus what I did 1:54 in last year.

"I've known I can go 1:51 for a long time, that's the way I've trained."

The US veteran had also lost to gold medallist Lochte in the 200m backstroke at the Beijing Olympics, and his 2009 worlds got off to a dismal start when an inexplicable mistake saw him fail to qualify for the 100m backstroke final.

Not surprisingly, Peirsol looked like a man on a mission. He took an early lead that he relinquished by a narrow margin at the 100m mark to Lochte before pouring it on in the final 100 to seize the crown.

"I wanted to win this," Peirsol said. "I saw that I pulled out at the beginning, and when I saw that I was pulling away that was like an extra fire in the belly to keep going.

"That was a fast heat, I don't know if I would have done that if I didn't have to."

Peirsol said his failure in the 100m backstroke may have helped him, since it gave him some extra time off.

"That was not a piece of cake, but I think I was more rested than everyone else. That was kind of a blessing in disguise," he said.

"I didn't get the chance to do the 100, obviously, in the week and a lot of my focus has been on this -- all of it has."

Irie broke down in tears on the podium and later explained that he had his mind set on gold and a silver was not what he'd come here for.

"I wanted to win but I came second. I'm very disappointed but I got my PB and I won a medal so I'm relieved," he said.

"I wanted to see the Japanese flag in the middle on the medal rostrum and it was such a shame not to see it there, that and the end of the race made me cry.