BEIJING (AP) Michael Phelps isn't convinced he's unbeatable.
Even so, Ian Crocker, considered one of the last two men standing between Phelps and Olympic history, will need to pick up the pace just to get a shot at him.
World record-holder Crocker finished 13th in 51.95 seconds in the 100-meter butterfly preliminaries Thursday as Phelps qualified second overall in 50.87. Only the top eight advance to the final, which NBC will showcase in its prime-time telecast Friday night.
Crocker longs to be one of those eight to resume his longtime rivalry with Phelps. Crocker set the record way back in 2005 and Phelps has pretty much owned him every time it's mattered since.
Phelps has won nearly every big race between the two, including the 2004 Olympics. Although Crocker avenged it with his record-setting swim at the 2005 world championships, Phelps has been pretty much unbeatable since.
Phelps beat Crocker at last year's world championships and the most recent U.S. trials, where he pulled away to an easy win.
"He is one of the great swimmers that's ever been around," Crocker said. "We've gone back and forth in this event for a long time. I'd like to end up in front."
Although Phelps was perfect through his first five swims - all record-setting gold-medal efforts - he's not taking the sweep for granted.
In addition to the 100 fly, Phelps had a Friday showdown with friend and teammate Ryan Lochte in the 200 individual medley.
"There are still three races to go, and I am not unbeatable," Phelps said before the 200 IM. "No swimmer is unbeatable."
American head coach Eddie Reese wasn't as certain, believing the momentum Phelps has will carry him to perfection.
"He is just sailing along this week," Reese said. "He's unstoppable."
Reese's endorsement isn't a good sign for Crocker, who trains under the coach all year. It's Crocker's only event of these games; whether that's a positive or negative remains to be seen.
"It's been a long week waiting and watching," Crocker said after the 100 fly prelims. "Finally I'm in the meet and tomorrow I can relax and do my race a little bit better."
Dara Torres, the self-proclaimed "old lady" of the U.S. team, makes her return to the pool when the 41-year-old tries to advance out of the semifinals of the 50 freestyle. She earned a silver in the 400 freestyle relay earlier in the games, and is hoping to earn her 11th medal dating back to 1984 in her final event.
Other NBC highlights will be the opening of track and field, including the gold medal of the shot put.
The quirky and charismatic American shot-putting trio of Hoffa, Christian Cantwell and Adam Nelson could very well sweep the Beijing Games' first track and field medals.
The race for the "world's fastest man" title also begins with preliminary heats of the men's 100-meter dash. Triple world champion and world record holder Tyson Gay of the U.S. readies for what should be one the greatest finals ever. He's expected to race against Jamaica's Usain "Lightning" Bolt and Asafa Powell for the gold medal.
The U.S. also plays China in men's volleyball.