After advancing to the finals of the 100-meter freestyle event in the morning trials, Michael Phelps crashed into seventh place at the Phillips 66 National Championships on Wednesday.

The 18-time Olympian had a decent trial time of 48.77 seconds in the event, but he admitted making a mistake at the first turn and failing to recover. He wound up with a time of 49.17 seconds.

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"It's kind of frustrating," Phelps said. "I felt really good after the morning swim."

Nathan Adrian won the event with 48.31 seconds followed by Phelps' long-time rival Ryan Lochte, 48.96 seconds. Olympic teammate Conor Dwyer placed fourth at 49.06 seconds.

Phelps never competed in the 100-meter freestyle event during his Olympic campaign, opting for events in the 200-meter range.

Bob Bowman, Phelps' longtime coach, said the Olympian's freestyle was on and off.

"We always did everything for a 200 before," said Bowman. "He's just getting used to that."

Phelps will compete on his trademark event, the butterfly, on Friday. He will only compete in the 100-meter event and not the 200-meter event, saying he wasn't in his top form to swim that distance.

Phelps holds the world record at the 100-meter butterfly at 49.82 seconds which he set during the 2009 World Championships as well as the 200-meter butterfly at 1:51.51.

Aside from the 100-meter butterfly, Phelps will also be competing in the 100-meter backstroke and 200 individual medley starting Saturday in Irvine, California.

The five-day nationals and the meet at the Pan Pacific Championships in Australia two weeks from now will be the testing ground for all swimmers.  Whoever records the fastest time will become members of the U.S. team that will compete in the 2015 World Championships in Beijing.

TagsBob Bowman, Ryan Lochte, Conor Dwyer, Nathan Adrian, swimming