Jenny Thompson during the 100m butterfly final at the US trials in Long Beach on Thursday. (Reuters)

Long Beach: Brendan Hansen upstaged Michael Phelps and Natalie Coughlin on Thursday when he broke the world record for 100m breaststroke on the second day of the US Olympic swimming trials.

Hansen, 22, split 27.93 seconds at the 50m turn before powering home in 59.30 seconds, almost half a second faster than the former world record of 59.78 set last year by Japan’s Kosuke Kitajima at the World Championships in Barcelona.

Four years ago at the trials, Hansen finished third in the 100 and 200m breaststroke, missing a Sydney Olympic berth each time by hundredths of a second. “After 2000, I was a man on a mission,” Hansen said. “The emotions from that meet have been with me every day of the last four years.”

Phelps, who set a world record in the 400m individual medley on Wednesday, clocked the fastest time in the 200m freestyle semi-finals on Thursday, 1:47.42. Klete Keller, who broke Phelps’ American record in the 400m freestyle, was close behind on 1:47.65. Coughlin posted the fastest semi-final time in the women’s 100m backstroke with 1:00.91. She holds the world record at 59.58 seconds.

The unheralded Rachel Komisarz, 27, came from behind to nip Jenny Thompson in the women’s 100m butterfly, touching in 58.77 seconds to Thompson’s 58.98. Kaitlin Sandeno (4:08.07) and Kalyn Keller (4:09.78), Klete Keller’s younger sister, took the two Olympic berths in the 400m freestyle. Defending Olympic champion Brooke Bennett finished seventh. Thompson, however, made the cut for Athens and dedicated the success to her late mother who died in February after a long battle with cancer. “I had a dream about my mom last night,” said Thompson. “She was really beautiful and happy. She was by the ocean... She’s in my dreams sometimes, but this was a rare one. ”

Thompson, whose ten Olympic medals over three Games include eight relay golds, retired after the 2000 Olympics to pursue her medical career.

But she missed swimming and gradually felt herself drawn back to the sport. As she heads for what she vows will be her absolutely final Olympics in Athens, she says she wants to remember the happiness her success gave her mother.

“In the past months I’ve been doing very well considering everything,” she said on the eve of the trials. “Swimming has been a safe place for me. I’m really glad I had that in my life. I’m feeling partly relieved. I was having mixed feelings after my morning swim. Something I can never take for granted is making the Olympic team,” she said.