SYDNEY, Australia (AP) _ Lenny Krayzelburg did the expected. Megan Quann did what she promised. Ian Thorpe did something different _ he lost.

Nervous being the heavy favorite, Krayzelburg came through in the 100-meter backstroke, winning another U.S. gold in an Olympic-record time of 53.72 seconds Monday.

Quann made it a double for the United States, backing up her prediction of victory over defending champion Penny Heyns of South Africa in the 100 breaststroke.

The 16-year-old from Puyallup, Wash., won in 1 minute, 7.05 seconds, but she was well off her intended target _ Heyns' world record of 1:06.52.

It was the fifth gold for the Americans in the pool in three days.

Thorpe, the Australian sensation who had already won two golds, lost a thrilling 200 freestyle race to Dutchman Pieter van den Hoogenband.

"In the last 25 meters, I was going full out," Van den Hoogenband said. "Suddenly, I thought, `God, he's not going to pass me."'

With millions of swimming-crazed Aussies watching on television and thousands cheering in person, van den Hoogenband staged the biggest individual upset so far in the pool. He tied his own world record in 1:45.35.

"I would like to have gone a little bit faster, but you don't always get it your own way," said Thorpe, who won the 400 freestyle and anchored Australia's upset of the United States in the 400 freestyle relay Saturday.

"I'm not going to win every race, I'm not going to break every world record. It just can't happen," he said.

Thorpe's silver medal came 24 hours after Van den Hoogenband broke Thorpe's world record in the semifinals. Thorpe finished second in 1:45.83. Massimiliano Rosolino of Italy won the bronze in 1:46.65. Josh Davis of San Antonio, Texas, was fourth in 1:46.73.

"The most amazing thing is to beat the overwhelming favorite," Van den Hoogenband said. "I think I already gave him a psychological blow yesterday."

Despite the win, Quann said she wasn't satisfied.

"I'd like to come out here, do it again and break the world record," she said.

Australian Leisel Jones won silver in 1:07.49. Heyns, who was first off the blocks and led until Quann passed her in the final 25 meters, took the bronze in 1:07.55.

"She has a lot of talent," Heyns said. "I really respect the way she's carried her successes. Unfortunately, you don't always say that about your competitors."

Krayzelburg led all the way in the 100 backstroke, bettering the old Olympic mark of 53.86 set by American Jeff Rouse at the 1992 Olympics. But he was .12 off his own world record, set in the same pool last year.

"You're measured in this sport by whether you win an Olympic gold medal. I'm glad I got one," he said. "It's better than anything I've ever done in my life."

Matthew Welsh of Australia won the silver in 54.07. Stev Theloke of Germany won the bronze in 54.82. Neil Walker of Verona, Wis., was sixth in 55.14.

Krayzelburg became a U.S. citizen in 1995, six years after his family emigrated to California from Ukraine. He is the defending world champion in the 100 backstroke and arrived in Sydney lacking only an Olympic gold medal.

"Oh my God, there's so much relief, you can't even imagine," he said. "The last 24 hours have been pretty hard. I thought I would stay pretty relaxed, but that definitely didn't happen."

Venue volunteers and workers had jammed every available nook of the pool to catch the showdown between the "Thorpedo" and the man nicknamed "Hoogie."

The rivals were even at the 150-meter mark, prompting cheers of "Thorpey, Thorpey" from most of the 17,500 fans, who were still roaring when the Dutchman pulled away in the middle of the pool.

"Beating Thorpe here is the maddest thing you can do," said Jan Loordach, the Dutch team leader, "and he's not finished yet."

Van den Hoogenband erased Thorpe's world record with a 1:45.35 in Sunday's semifinals. Thorpe swam the next heat and missed taking the record back by two one-hundreths of a second.

The 17-year-old Thorpe denied his country's expectations or the hype that has him on the front pages of newspapers nationwide took its toll.

"Maybe I was just a little flat from the first day, but I've got to work around it," he said. "They're not going to change the Olympic program."

After the race, the fans cheered for Van den Hoogenband and then got noticeably quiet. He covered his face with his hands before climbing out of the pool and blowing kisses to the crowd.

"We came to the lion's den and we did it," said Cees-Rijn van den Hoogenband, Pieter's father.

Van den Hoogenband just missed medals in the 100 and 200 freestyles when he finished fourth at the 1996 Atlanta Games. He established his reputation last year by beating Olympic champion Alexander Popov of Russia in the 50 and 100 freestyles at the European championships.

Van den Hoogenband gave a tiny nation best known for soccer and speedskating its second gold medal and world record in swimming in as many nights. On his way to the medals podium, he high-fived Inge de Bruijn, who won the women's 100 butterfly Sunday.

Thorpe's time was nearly a half-second slower than his semifinal effort. Afterward, he ducked into Van den Hoogenband's lane to congratulate his conquerer.

Diana Mocanu became the first Romanian swimmer to win a gold medal, taking the 100 backstroke in an Olympic record 1:00.21. Mocanu, who was third at 50 meters, won Romania's first swimming medal since 1988. She broke the old mark of 1:00.68 set by Krisztina Egerszegi of Hungary at the 1992 Olympics.

Mai Nakamura earned silver in 1:00.55, giving Japan its first backstroke medal since 1960. Nina Zhivanevskaya of Spain took bronze in 1:00.89. B.J. Bedford of Etna, N.H., was sixth in 1:01.47 after being second at 50 meters.

American Tom Malchow of St. Paul, Minn., broke the Olympic record for the second time Monday in the 200 butterfly semifinals. Malchow qualified first in 1:56.02, lowering the mark he set in the morning prelims.

"I'm getting faster and faster, which is a good sign. I still feel like I'm in pretty good control," Malchow said. "Time is not a concern. I just want to get a gold medal."

Michael Phelps, a 15-year-old from Baltimore who is the youngest U.S. Olympic male swimmer since 1932, was fourth-quickest in 1:57.00.

Russia's Denis Pankratov, the defending Olympic champion, grabbed the eighth and last spot in 1:57.24.

Australia's Susie O'Neill led all qualifiers for the 200 freestyle with a semifinal time of 1:59.37.

Franziska van Almsick of Germany, the world record holder, failed to advance to Tuesday's final. She was 11th in 2:00.26.

Americans were shut out of a final for the first time in the meet when Lindsay Benko of Elkhart, Ind., and Rada Owen of Chesterfield, Va., weren't among the top eight. Benko was 12th in 2:00.27, while Owen was last among 16 swimmers in 2:03.34.

Yana Klochkova of Ukraine, who won gold in the 400 individual medley Saturday, was the quickest qualifier for the 200 IM final in 2:13.08.

Cristina Teuscher of New Rochelle, N.Y., was third-fastest in 2:13.47, while Gabrielle Rose of Memphis, Tenn., was seventh in 2:14.40.

(Copyright 2000 by The Associated Press. All Rights Reserved.)