The biggest question-mark is whether he can handle big names or provocative managers like Jose Mourinho, who he will face when Chelsea visit Old Trafford on the second weekend of the Premier League season.
"I'm relishing it all. When you're a boy from Glasgow, you're quite 'gallus'," he told the Mail on Sunday. "It's a term we've got up there - it means you've been through a lot. So I've no problem with Jose or whatever other people might say. I look forward to it.
"I've had to battle my whole managerial career. I remember getting the Preston job and people saying it shouldn't be me but a bigger name like Joe Royle or Ian Rush. So I think this job will come with pitfalls. There will be questions about what I do. Hopefully I'm tough enough to stand up for myself."