Campbell, 26, insists he had no regrets about quitting United as his Cardiff side prepare to tackle David Moyes' men.
He said: "It was difficult to leave United. I'd been there since I was ten.
"Then they brought in Carlos Tevez. I had to be worth £25million to be playing in that team!
"I had a great time there. I didn't play many games but it was nice to be part of the club."
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