He added: "I don't think it is anything to do with his chin - if anybody watches the tape back they will see that it was a tremendous punch that he got clipped with.
"But he got straight back up. Obviously he got up again and the same thing happened.
"His problem is his heart. He rushed out as soon as the bell went, tried to take the fight to the guy rather than have a look at him and he paid the price.
"In his last couple of fights when he has been caught, he has got straight back up and has gone on to win the fight, and even the round.
"But he does drop his hands and gets caught. That is what schooling and learning is all about. Unfortunately Prescott was not the type of opponent to get that schooling from.
"Amir was the architect of his own defeat. If he is going to go on and do the things that we all hope he can do, it is a painful lesson he will have to learn.
If you are going to be ready for a world title fight, you have to be ready for the Prescotts of this world
"But if he is bright and intelligent enough - which I think he is - he will learn from it."
Warren also feels that Khan will still need to be tested when he is finally ready to make his comeback, in order to kick-start his development.
"I think he will have to go in with somebody again who is going to give him something to think about it," he said.
"If you are going to be ready for a world title fight, you have to be ready for the Prescotts of this world."
Warren admitted that he was concerned about the danger posed by the Colombian even before the fight and added that he should never have set up the fight on the recommendation of Khan's new trainer Jorge Rubio.
"I was a bit nervous before the match. I did take the recommendation from Rubio and I should not have.
"I have got to take the responsibility but I am a little bit disappointed how much Prescott was recommended."
Khan made it clear he is determined to rectify his errors, while also handing a vote of confidence to Rubio - who replaced Oliver Harrison after the Salford trainer was sacked earlier this year .
"Sometimes I let my heart rule my mind and it showed," said Khan. "I've been hit harder in my career but it was just at the wrong time, too early in the fight before I could get into it.
"I'm not going to let it get to me. Every fighter wins and loses in their career and I'm just going to come back stronger. Me and Jorge will work on my mistakes."
"Training went really well but I happened to get caught with a shot by a power puncher."
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