The Lions are 11 points off safety with only six games remaining.
But Duffy said: “There are still points to be played for.
“Our focus is just week-to-week and improving ourselves, especially in defence.”
Halifax could be boosted by the return of Ryan Fieldhouse, who missed last week’s win over Whitehaven due to food poisoning.
Halifax’s win kept them just two points behind second-placed Featherstone Rovers.
Coach Karl Harrison believes the race for a top-two finish is far from over.
Harrison said: “It’s a three-horse race to be truthful, and I think it’ll go down to the very last weekend of the competition. The Championship is a tough competition, and I’ve said that from day one.”
Halifax only conceded two tries against Whitehaven, both in the last six minutes of the match, but Harrison is still searching for perfection.
He said: “We need to be better defensively in the bigger games, certainly in terms of handling kicks.”