Sunday's opponents Celtic haven't been able to shake off the Dons while other challengers Inverness and Dundee Utd faded away in 2015.
And the Reds' 3-0 win over St Mirren at the weekend – part of a 13-game unbeaten run – keeps the pressure right on the champions.
McLean is already convinced the on-form Dons can take all three points from Celtic Park and prove once and for all that the Dons are genuine Premiership challengers.
McLean told RedTV: "It is massive. Since I came to the club everyone has been talking about this game.
"Our confidence is up and we are playing well. We’re scoring goals and defending well. We’ve scored 10 goals in our last three games and not conceded.
"Can we beat them? I don’t see why not. We have the quality in the squad to beat anyone and there is a real winning mentality."
Source: RedTV