Michael Phelps feels the pain as he flops at Pan Pacifics

Michael Phelps failed to qualify for the 400 metres individual medley final at the Pan Pacific Championships on Thursday after competing in the event for the first time since the 2008 Olympics.

Although the fatigued world record holder recorded the fourth-fastest time in the morning heats, clocking four minutes 15.38 seconds, he was beaten by two of his team mates.

Only two swimmers from each country are allowed to compete in the eight-man final and fellow Americans Ryan Lochte and Tyler Clary each dipped under the previous Pan Pac record to finish first and second in the opening heat.

World champion Lochte touched in 4.08.77 with Clary close behind in 4.09.20 in dazzling sunshine at the William Woolett Jr. Aquatics Center. Brazil's Thiago Pereira was third fastest, winning the second heat in 4.15.35, before Phelps missed out on qualifying after dominating the third and final heat.

"Gosh, I shouldn't have done it. That was painful," Phelps told reporters. "I was expecting 4.10 or 4.12 this morning, and then go for it tonight. For them to go 4.08, 4.09 - that's a very, very solid swim.

"Looking at my splits, it's not terrible. I'm trying to think of how many other times I've been faster than that in a prelim. I definitely wasn't expecting those boys to fire one-off like that from heat one."

Phelps had said this week he was in relatively poor shape coming into the event. "I am probably between a four and five out of 10, so not too hot," the 25-year-old added. "I knew coming into that race it was going to be a rather painful way to sort of wake me up. It just wasn't there. I don't remember it ever being that painful but I guess it's a good reminder that I need to be in a whole lot better shape."