Rome, July 28 (DPA) An astonishing eight swimmers managed to swim under the championship record in the heats of the men’s 50m breaststroke, as the third day of swimming got underway Tuesday at the world championships here.

Also in action early Tuesday was American superstar Michael Phelps, who comfortably qualified for the semi-finals of the men’s 200m butterfly.

In the women’s 200m freestyle heats, Swedish teenage sensation Sarah Sjostrom, who has already broken two world records and has won one gold medal, failed to qualify for the semi-finals.

The 15-year-old, who is not considered a 200m freestyle specialist, finished her heat in a time of one minute 58.58, well behind American Dana Vollmer, who had the best time in 1:55.98.

Her compatriot Allison Schmitt had the second-fastest time, 0.77 seconds behind Vollmer.

In the men’s 800m freestyle, it was Oussama Mellouli who lead the swimmers into the final. The Tunisian swam a 7:41.82, edging out Canadian Ryan Cochrane by nearly two seconds.

Italian Federico Colbertaldo was cheered as he won his heat in a time of 7:44.29 for the third-fastest time.

In the men’s 200m butterfly Phelps was in complete control in his heat and although he did not qualify for the semi-finals with the fastest-time, he was just one place below Poland’s Pawel Korzeniowski, who topped the qualifying with a time of 1:54.33.

Phelps was just two hundredths slower, while his compatriot Scott Tyler Clary was third-fastest.

Phelps said that he was happy with his swim. “I just wanted to win my heat, that is all I wanted to do. One of the biggest things about that event is getting into the finals.”

He added that he wanted to reserve much of his energy for the finals of the 200m freestyle, which will be held Tuesday evening. “My big race is tonight, the 200m free is the first event.”

His compatriot Clary, who tore his swimsuit before the race, said that he had had taken 25 minutes to get ready. “It took me 25 minutes to get into the suit.

“My coach just told me to calm down and he helped me focus on the race, so I am pretty pleased with my time under those circumstances,” he said.

But it was in the breaststroke where the most impressive performances were shown.

Ireland’s Barry Murphy achieved a surprising championship record for his country in the 12th heat, when he finished in a time of 27.26, beating the previous best mark from South Africa’s Cameron Van den Burgh by .12 seconds.

His record stood for just three heats though, as Australian Brenton Rickard managed to swim 0.11 seconds faster.

His time was then broken by Van den Burgh in the very next heat, with the South African coming within three hundredths of a second of breaking Felipe Franca da Silva’s world record.

The Brazilian swam a 26.89 earlier this year and qualified for the semi-finals with the second-fastest time.

On Tuesday evening the finals of the men’s 100m backstroke and the 200m freestyle, as well as the women’s 100m backstroke and breaststroke and the 1,500m freestyle will be swum.

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