The Antrim man, 30, begins his Crucible quest full of confidence after winning the Players Championship last month, his third success in a ranking event.
“I think he will try to slow the match down and try to drag me down a little bit,” said the world number seven.
“But I don’t think he can outscore me or outplay me in any way,” added Allen.
Allen said playing at snooker’s showpiece event in Sheffield continues to provide a huge buzz and understandable anxiety, but he expects Mann to be affected by nerves.
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Allen added: “It’s his first time at the Crucible and I remember my first time and thinking, ‘just don’t fall down the steps’.
“It is so nerve-wracking. And it is still nerve-wracking now. You would think you would get used to it but it’s a different sort of pressure here. It is an unreal experience.
“Mitchell is a good lad, a cracking guy. Hopefully he can come here and embrace it, but not too much.”
The former world semi-finalist knows he carries the burden of expectation from home as he looks to become the first Northern Ireland player to win the world title since Dennis Taylor in 1985.
But that will be a long way from his thoughts when he starts his match this afternoon.
“I do understand and appreciate the support I get from back home,” Allen said. “There is a massive following. People you don’t expect to be watching snooker watch when I am playing.
“It’s great but I don’t think about that when I am playing.”