The Eagles star earned a dream transfer from Selhurst Park to the Theatre of Dreams six years ago, but only ended up staying at the club for two years before returning to familiar surroundings.
Zaha, who was the legendary Sir Alex Ferguson's last signing before retiring, was unable to break into the United first team under David Moyes or Louis Van Gaal, taking in just four appearances in total across all competitions.
He had spells on loan at Cardiff and Palace before securing another permanent contract with the Eagles in 2015 and he has since managed to rebuild his damaged reputation.
Neil Warnock was the man in charge at Selhurst Park at the time of his return and is preparing to welcome his old club to Cardiff City Stadium on Saturday.
Ahead of the crucial Premier League clash, the Bluebirds coach has revealed how Zaha's time at United negatively impacted his confidence.
“He wasn’t in a good place. I met him in the chairman’s office," Warnock said at a press conference on Friday.
"We were talking to him and it was obvious how he felt when he had been let down by Manchester United. When I spoke to him I could understand why.
"He was only a young lad then, he needed help and an arm around the shoulder. It didn’t appear that he got any of that.
"That is what you do, you go away, rekindle that enthusiasm.
"He has always had tremendous skill and in the next few years I am sure he will go to one of the top few clubs in Europe."
The Red Devils have reportedly been keeping a close eye on Zaha's progress in recent years, but it is understood he will ignore any potential offers to remain with Palace for at least one more season, with his current contract set to run until 2023.
The 26-year-old has been a key figure for Roy Hodgson's side once again this term, contributing nine goals and three assists in 32 Premier League appearances.
Palace have already guaranteed their place in the top flight for another year and after facing Cardiff they will wrap up their season at home to Bournemouth on May 12.