The Terriers ended a run of 13 league games without a win thanks to James Vaughan's fifth goal for the club during a heated encounter at the Galpharm.
"That will do him the world of good. Lee Novak scored on Saturday and Vaughany scored tonight and they will take confidence from that," Lillis told reporters.
"The confidence is starting to return to all the players and that's what happens when you work hard, tackle and fight.
"Neil Danns was shouting to me that his calves were cramping up and I shouted back 'that's good'. That's what I want - for players to come off with their tongues hanging out, all sweaty."
The result moves Huddersfield up to 16th place in the Championship, while Palace remain in fifth.
Palace boss Ian Holloway refused to give media interviews following reports of verbal altercations in the tunnel after the game.