Cas are yet to win a game after two rounds of Super League, having lost by two points to neighbours Wakefield on the opening weekend of the season.
They followed that up with a narrow 13-12 defeat in Perpignan at the hands of the Catalans Dragons, and Cunningham is expecting them to have improved in the last two weeks since that game.
“I spoke to Daryl Powell in preseason, and he’s brought a lot of new players and new faces in, which is a big change for him,” said the Saints coach.
“But Daryl’s a great coach, and my feeling with Castleford is the longer they go into the season, the better they’re going to get.
“Those players will get used to playing with each other and what works and what doesn’t work.
“They’ve got new halves coming in who need to learn to play with each other, a new hooker who’s got to learn to play with his halves.
“Every week they get better and better. You can see from week one when they played Wakefield at home.
“When I watched that game they really should have won the game, Cas were the better side at the time.
“Then week two, when they’ve had chance to play with each other a little bit more, they go over to Catalans and it was 50-50, it could have gone either way, it was a close game.
“For anybody to go to Catalans and get to within the result has got to be a decent side for me. It’s a tough place to go.
“With the travel and everything off the back of it.
“They’ve had more or less two weeks to prepare for our game, and they’ll come in a better side again.
“You can’t take any game lightly in Super League any more. Those days are long gone.
“You’ve got to prepare well every week, because you need those points.”
Saints are back in action just a few days after losing the World Club Challenge match 39-0 to South Sydney Rabbitohs.
Cunningham wants to give the Saints fans something to cheer them up after such a mauling by the NRL team.
“The sooner the game could come round, the better for us,” he said.
“We’re back at home, and we owe the fans a good performance. We owe ourselves a good performance.”