Omaha, NE (My Sportsbook) - Cullen Jones broke the American record in the men's 50-meter freestyle during the preliminary heats Friday at the U.S. Olympic Swimming trials.

Jones, trying to become the second African-American swimmer to qualify for the Olympics in an individual event, finished in a time of 21.59 seconds to advance to tonight's semifinals.

"I think there's a lot more in the tank, so we'll see what can happen tonight," said Jones, whose hometown is New Brunswick, NJ.

Afterward, Jones acknowledged he took just one breath during the race.

The old record of 21.76 stood for eight years and was held by Gary Hall Jr. Hall, attempting to make his fourth Olympics and the two-time defending champion in the event at the Summer Games, also made it to the semifinals with a time of 21.89.

Hall's mark was third-best in the preliminary heats. Ben Wildman-Tobriner was second at 21.68. Garrett Weber-Gale, the winner of Thursday night's 100-meter freestyle final qualified at 22.05, tied with Nathan Adrian and Jason Lezak in fourth.

On Thursday, Jones finished third in the 100-meter freestyle final and was named to the relay team. He's just the third African-American swimmer in the history of the U.S. Olympic squad, joining Anthony Ervin and Maritza Correia. Ervin tied Hall for the gold medal in the 50-meter freestyle at the 2000 Olympics.

Kate Ziegler had the top qualifying mark for Saturday's final in the women's 800 meter freestyle with a time of 8 minutes, 29.39 seconds. Katie Hoff, who already won four finals at these trials and has qualified for five events at the Olympics, was next at 8:29.91. Ziegler was second to Hoff in the final of the 400-meter freestyle on Monday.

"Kind of a smaller version of my race for tomorrow night, obviously not giving it 100 percent, but trying to get a good, solid feel for it," said Hoff, who later dropped out of the 200-meter backstroke.

In those preliminary heats, Elizabeth Beisel had the top qualifying time at 2 minutes, 7.44 seconds. Those semis are tonight and the final is Saturday. The time set an U.S. Olympic trials record, besting the mark of 2:09.43 from Janie Wagstaff in 1992.

Hayley McGregory had the second-best time at 2:08.76, while Margaret Hoelzer, the American record-holder, was next at 2:10.19.

Ian Crocker's time of 51.52 seconds was the best among qualifiers in the preliminary heats of the men's 100-meter butterfly. The semifinals are tonight and the final is Saturday.

Michael Phelps was second-best at 52.21, with Gil Stovall (52.26) and Davis Tarwater (52.32) next in line.

"The 100 fly was the gift that I was given," said Crocker, who has held the world record for nearly three years. "You want to shake your money-maker and see what happens."

This was the first official result of the week for Crocker, who was disqualified in the preliminary heats of the 100-meter freestyle.