Japan's Ryosuke Irie won the silver medal in 1:52.51, while Peirsol's compatriot Ryan Lochte, who earlier in the week won the 200m individual medley, took the bronze 1.90 off the pace.

Peirsol, who sensationally was eliminated in the semi-finals of the 100m backstroke said that could have worked in his favour. 'I was more rested than I thought, it was probably a blessing in disguise.

'Winning the gold medal makes up for it. I moved on after they swam the finals. I was very motivated for this race.'

Hungarian outsider Daniel Gyurta took the gold medal in the men's 200m breaststroke, winning in a time of 2:07.64, beating American Eric Shanteau by just one hundredth of a second.

Australian Christian Sprenger, who on Thursday broke a world record in the event, shared bronze with Lithuanian Giedrius Titenis.

There was also an unexpected gold medal for Serbia in the women's 200m breaststroke as Nadja Higl came through on the last 50m to move from third into first, winning the gold medal in a time of 2:21.62.

The silver medal went to Canadian world record holder Annamay Pierse in a time of 2:21.84, while Austrian Mirna Jukic won the bronze medal .35 seconds off the pace.

There was further joy for Serbia as Cavic, who had earlier in the day offered to buy Michael Phelps an all-polyurethane bodysuit, broke the world record in the semi-finals of the 100m butterfly in a time of 50.01 seconds.

Phelps had the second-fastest time in 50.48.

Zimbabwean Kirsty Coventry, who is still waiting for her first medal of the championships, led the field into the final of the women's 200m backstroke with a championship record time of 2:05.86, beating Russian Anastasia Zueva by 1.14 seconds.

In the semi-finals of the women's 50m butterfly Dutchwoman Veldhuis broke her own world record in a time of 25.28, taking seven hundredths of a second off her old best mark.

But that time was beaten in the second semi-final by Sweden's Alshammar, who came close to breaking the 25-second barrier. She won her heat in a time of 25.07 to go through to Saturday's final.

In the semi-finals of the men's 50m freestyle French world record holder Frederick Bousquet managed to break the championship record when he qualified for the finals in a time of 21.21.

In the first heat, Croatian Duje Draganja had already broken the championship record with a time of 21.29, only to see Boiusquet go even faster.

Brazilian Cesar Cielo Filho, who on Thursday won the men's 100m freestyle in world record time, went into the final with the fourth-fastest time.

The championships, which started on July 17, end Sunday.