MELBOURNE - American Michael Phelps did it again, setting his second world record in as many nights.

Michael Phelps of the US gestures after winning the men's 200m butterfly swimming final at the World Aquatics Championship in Melbourne March 28, 2007. Phelps won the race with a new world record time of 1:52.09. [Reuters]

He was joined in the world record parade Wednesday at the world swimming championships by fellow American Leila Vaziri and Laure Manaudou of France.

Phelps broke the 200-meter butterfly in a time of 1 minute, 52.09 seconds. It bettered his own mark of 1:53.71 set on February 17 of this year in Columbia, Missouri.

"I surprised myself, I went so fast," said Phelps. "I wanted to go 52.00 but I didn't expect to swim 52.00.

"I'm showing I'm in solid shape now. I had a really good swim earlier in the season where I broke the world record. I wanted to take it out tonight, so I'm pretty happy."

Wu Peng of China took the silver and Nikolay Skvortsov of Russia was third.

Vaziri set the world 50-meter backstroke record in a semifinal. Her time of 28.16 seconds broke the previous mark of 28.19 set by Janine Pietsch of Germany in Berlin on May 25, 2005.

Manaudou, who won the 400 freestyle gold Sunday, set her new mark in the 200-meter freestyle, finishing in 1:55.52, breaking a 24-hour-old record set by Italian Federica Pellegrini of 1:56.47 in Tuesday's semifinals.

Second-place finisher Annika Lurz of Germany also bettered Pellegrini's record, finishing in 1:55.68 Wednesday. Pellegrini took third place in the final in a time of 1:56.97.

Manaudou, talking to French television, said she was inspired by the world record performances by others Wednesday.

"I told myself I had to have one, too," said Manaudou, who pulled out of the 50-meter backstroke semifinal two races earlier Wednesday to conserve her strength for the 200 freestyle.

Oleg Lisogor of Ukraine won the men's 50 breaststroke, an event that is not in the Olympics. He finished in 27.66 seconds, beating out American Brendan Hansen by 0.03 seconds.

Hansen took the silver in 27.69. Cameron Van Der Burgh of South Africa earned the bronze. Japan's Kosuke Kitajima was fifth.

Just as he did in winning the 200 freestyle, Phelps raced to the lead and stayed there, touching in 1 minute, 52.09 seconds.

Phelps simply crushed his rivals, beating silver medalist Wu of China by 3.04 seconds. Phelps already owned the seven fastest times in history in the event.

The 21-year-old American was under world-record pace the entire race, and extended his lead at every turn.

At 100 meters, he dipped 1.65 seconds under his mark and stretched it to an amazing 1.78 seconds through 150 meters as fans in Rod Laver Arena cheered louder and louder.

Phelps was going so fast, the red line that tracks world record pace was actually behind him. He cruised home nearly two body lengths and a world away from Wu, who finished in 1:55.13 for China's first medal of the swim meet.

Phelps hit the wall, turned around and raised both index fingers in the air, signaling his two world records so far.

Phelps is 3-for-3, with victories in the 400 freestyle relay, the 200 free and 200 fly. He set a world record in defeating Pieter van den Hoogenband of the Netherlands by 2{ seconds in the 200 free Tuesday.

After that effort, Phelps came into his latest final exhausted, his arms still tired from the night before.

"I felt horrible. I felt horrible in the warmup pool," he said. "But it looks like things are rolling in the right direction."

Indeed, Phelps remains on track to win eight golds.

Still left are the 200 and 400 individual medleys - he holds the world record in both - and two more relays that are strong possibilities for US gold.