Cougars fell to a 24-10 defeat at Whitehaven last week, leaving Demetriou to call for an improvement in his side’s attitude.
He said: “We were out-enthused, and they were more aggressive than us. We’ve set standards that we want to match every week, and we didn’t live up to those in the first half.
“However, the reaction of the boys after the game and during training has been very good. I’m confident we’ll put up a different performance on Sunday.”
He added: “Oldham have only won one from three, so that’s going to make them very determined, and they’re always a top team in this division. We’ll have to be prepared.”
Oldham coach Tony Benson continues to battle against a mounting injury crisis.
Jack Bradbury and Sean Robinson are the Roughyeds’ latest doubts having sustained dead legs during the 68-24 defeat against Swinton.
Luke Sutton (quad) also faces a fitness test on Thursday night before Benson decides his team.
Benson said: “It’s very difficult at the moment.”
He added: “It’s just continuing inexperience, not just on how to play the game but also on how to react. Swinton did well at targeting our weaknesses last week.
“Keighley are one of those teams that are very difficult to beat at home. We haven’t won there for a while, but that gives us something to aim for. We’re certainly set up with that goal in mind.”