DUBAI, United Arab Emirates — Olympic champion Cesar Cielo, American rival Nathan Adrian and French standout Frederick Bousquet appear set for a foam-filled sprint off at the short-course world championships.
Also Thursday, Americans Ryan Lochte and Natalie Coughlin registered top qualifying times in their heats.
Attempting to reinforce his mantle as the world's fastest man in the pool, Brazil's Cielo led the 50-meter freestyle heats Thursday in 21.06 seconds, 0.05 seconds ahead of Adrian, with Bousquet third, 0.06 back.
Cielo won the 50 free at the 2008 Beijing Games and then swept both sprints — the 50 and 100 free — at the 2009 long-course worlds in Rome. But he failed to win over both distances at the Pan Pacific championships in August, where Adrian prevailed.
Having worked exclusively with Brett Hawke at Auburn University the past few years, Cielo has been spending more time at home in Brazil lately with his old coach Alberto Pinto.
"Water is water. I have a lot of confidence in both coaches," Cielo said. "I'm feeling confident and in shape and I think that's what matters most."
The 50 free semifinals are scheduled for later Thursday, with the final Friday. The 100 will be decided on Sunday, the last night of competition at the Hamdan bin Mohammed bin Rashid Sports Complex.
Lochte led the 400-meter individual medley in 4 minutes, 1.76 seconds, improving on his own championship record from four years ago.
Lochte already won his first gold of this meet in the 200 free Tuesday, but saw his bid for eight golds prematurely ended when the U.S. squad finished an unexpected fourth in the 400 free relay.
The relay loss means Lochte won't have to answer too many more questions about matching Michael Phelps' record eight golds in Beijing.
"I usually don't put any kind of pressure on me, so I'm just going out there racing tough and having fun," he said.
Olympic 1,500-meter champion Oussama Mellouli was Lochte's top challenger again, finishing 0.51 behind.
"I'm just playing around with the 200 free and 400 IM before I get to swim my own event," Mellouli said, looking ahead to the 1,500.
In Thursday's evening session, Lochte will swim the 400 IM final plus the 800 free relay.
Coughlin, a three-time Olympic champion, swam 52.57 in the heats for the 100 free.
"In the past month my freestyle has been feeling really good and this only solidifies that," Coughlin said. "I think I can improve on this swim and go faster."
Another American, Ariana Kukors, set a meet record in the 100 IM, clocking 59.14 to eclipse Jenny Thompson's mark from 1999.
There was also a championship record in the women's 50 butterfly, with Sweden's Therese Alshammar touching in 25.23, 0.18 ahead of Australia's Felicity Galvez, who won two golds in Beijing.
While Cielo's main competition should come from Adrian and Bousquet, he'll also have to watch out for Swedish veteran Stefan Nystrand, who qualified sixth, and Olympic 100-meter champion Alain Bernard of France, who tied for seventh.
South Africa's Roland Schoeman, who holds the world record of 20.30, narrowly made the semifinals in 15th, 0.64 behind Cielo.
The world record appears far off after high-tech bodysuits were banned at the start of this year.
Not one individual world record has been set in 2010.
"I don't think they're out of reach, but I think they're very hard — 20.30 is very fast right now," Cielo said. "I don't think anybody is going to do it in this meet, but it's always great to have a higher goal to push us. Who knows? Somebody might go faster than that, but I think it's going to take a while to break."
However, Cielo is picking Lochte to break a world record in the 200 IM on Friday.
"He can probably (set records) in some more events, but that will probably be the first one," Cielo said.