Kazan: Anthony Ervin admitted the USA men`s relay team were stunned after failing to reach the 4x100m freestyle final for the first time in world championships history on Sunday.
The experienced USA quartet of Jimmy Feigen, Ervin, Matt Grevers and Conor Dwyer won their heat, but their time of three mins, 16.01 secs was only the 11th fastest with only the top eight teams going through to Sunday night`s final.
"I honestly don`t know," said a stunned Ervin when asked for an explanation.
"We`re stunned by the overall results. We have just got to go back and analyse it.
"Jimmy looked pretty good coming in, I felt good going out.
"I died real bad at the end of my leg, which is not uncommon.
"I didn`t really see the rest of the relay, I was still kind of rolling around in a bit of a lactic acid blackout."
Having won the silver medal two years ago when the world championships were held in Barcelona, the USA had been one of the favourites for gold in Kazan along with reigning champions France and hosts Russia.
The USA had been so confident of qualifying that they rested their top stars, which is not uncommon in the heats, but paid the price for resting Olympic 100m freestyle champion Nathan Adrian and 15-time world gold medallist Ryan Lochte.
Ervin said there was no hint of the disaster to follow in their training and preparation, but the 2000 Olympic 50m freestyle champion was struggling for breath in the mixed zone.
"We had felt good going in," panted the 34-year-old.
"We all thought we were feeling good and confident.
"We thought we were going to send a little bit of a message this morning.
"We saw the clock and it was just like `whoa!`.
"The number just seemed so off."