Former Aberdeen striker Lee Miller believes Derek McInnes' men cannot afford to lose to Celtic on Saturday.
The Dons finished second to Ronny Deila's side close in the league last season, but lost all four Scottish Premiership matches between the pair.
And Miller says if they are serious about mounting a title challenge, defeat at Pittodrie is not an option.
"They have to show a good account of themselves, they can't get beat," Miller told BBC Scotland.
Aberdeen have equalled their best ever start to a league campaign with five wins out of five.
Victory on Saturday would take them two points above Celtic and with a game in hand.
"I think Derek McInnes will be adamant to the players in the dressing room that they have a massive chance this season," said Miller.
"If they want to be serious title challengers they can't get beat."
Miller tasted success for the Dons against Celtic when he was at Pittodrie; being part of the side that knocked Gordon Strachan's men out of the Scottish Cup in 2008.
He believes his old club are strong enough to mount a sustained challenge.
"Derek's recruited very wisely," added Miller. "He must have two players for each position, and you need that because it's a long season - suspensions, injuries.
"And it's quality in his pool of players and they're reaping the benefits."