Phelps was himself in the Men's 200M Freestyle.
He jumped out to an early lead and finished in first place after swimming a 1.45.70.
Ryan Lochte looked capable of finishing on top in the last quarter turn, but Phelps pushed to take the lead.
Lochte clocked in second place at 1.45.75.
Joining Lochte and Phelps in London, after finishing in third and fourth place, will be Ricky Berens and Dwyer Conor.
Missy Franklin and Rachel Bootsma, the two teenagers, will be going to their first Olympics.
Franklin broke the American record after swimming a 58.85 in the 100M Backstroke.
She had just finished participating in the Women's 200M Freestyle Semi-Finals and still managed to win this race.
Matt Grevers and Nick Thoman won the Men's 100M Backstroke.
They posted a 52.08 and 52.86 respectively. For Thoman, it will be his first trip to the Olympics.
Women's 100M Breaststroke was close at the end. Three swimmers could have been won but Breeja Larson and Rebecca Soni finished ahead of the pack.
Jessica Hardy became the odd woman out in this race.
Larson finished in 1.05.92, while Soni posted a 1.05.99.
This will be Larson's first Olympic competition.
In the 200M Butterfly, Tyler Clary and Mark Dylla finished in first and second place in the first set of the semis.
Davis Tarwater and Bobby Bollier beat Phelps in the Semi-Finals race, but Phelps still made it to the Finals, which will take place tomorrow. Michael Flach, Dan Madwed and Dakota Hodgson will also participate in the 200M Butterfly Finals.
