It's in the managerial rule book to talk up your opposition. Phrases like "there are 10 clubs that could win the premiere league" and "there are no easy games.." are commonplace.
I would love to see a manager say "I think they'll work hard but we believe we're a better team, so I think we'll win by two clear goals".
They do it in cricket: Glenn McGrath "I predict a 5-0 whitewash".