Amir Khan has blamed a change of trainer and style for his below-par performance against Samuel Vargas.
The former world champion was dropped by Vargas last September before going on to outpoint the Colombian.
Khan had Joe Goosen in his corner that night after regular trainer Virgil Hunter suffered a life-threatening illness.
And he is confident a reunion with Hunter will propel him to an upset victory over Crawford on April 20.
"[Virgil has] known me for a long time, so it's always better to be with someone who knows you and your fighting style," Khan told ESPN .
"As you get older it gets harder [and] when you go to a new trainer, it can be hard to adapt to their ideas. Joe Goossen did a great job with two warm-up fights, but I've decided to go back to Virgil.
Amir Khan's withering assessment of Terence Crawford's opponents
"There were a lot of wobbly moments in my last fight and I should have stopped him [Vargas] or knocked him out - he should never have been in the same ring as me.
"Luis Collazo just beat him and that shows you; I beat Collazo quite comfortably five years ago.
"But it was because of a change of trainer and a change of style and everything happened so quickly. That's when I realised I should go back to training under Virgil."
Meanwhile, Khan has been joined in San Francisco by Chris Eubank Jr who is working with Hunter.
Chris Eubank Jr training with Amir Khan coach Virgil Hunter
The son of a legend said: "I’ve seen what Virgil has done over the years, but I wanted to see it up close in person and work with him a little bit, just to see how it is.
"It’s just exploring, Virgil’s not my new trainer. I’m just having a little dabble.
"It absolutely could turn into something, but you can never tell how life is going to turn out."
