The 54-16 defeat by derby rivals Wakefield was the Tigers' fourth successive reverse since toppling Saints on April 6.
But Cas boss Matterson (pictured) - stung by the nature of his side's Cardiff capitulation - still has faith in his squad. And he insists he will lift morale for the next match - a home match against Bradford Bulls at the Jungle a week on Sunday.
"It's not a fitness thing, it's about confidence," he said. "Two weeks is a long time in rugby league and I've no doubt that we can turn it around. It starts in training.
"We'll get some hard work into them and build confidence. I think in a way we need to start our season now. We've done some good things in the first half of the season but didn't win enough games. It's time to draw a line in the sand and move forward.
"I've still got confidence in them because I've seen what we can do."
Cas shipped four tries in less than ten minutes against the Wildcats on Saturday, leaving them 24-0 in arrears in as many minutes.
Injuries to club captains Awen Guttenbeil and Brent Sherwin restricted Matterson's options and Wakefield punished some half-hearted play to run in five second-half touchdowns.
"In five sets they scored four tries and kicked a 40-20. In total they had ten of the first 12 sets, which made it very difficult, said the Cas coach.
"That was because of us dropping the ball, our last-play options were poor, we didn't support and we didn't run as hard.
"The bottom line came down to who wanted it more - and that was a real tough one to take, bearing in mind who we were playing and what was riding on the game.
"Losing both your captains does not help but the cracks were there before that. And it's disappointing that no-one else put their hands up and led the way, which some have done in the past.
"We've got a week off and that gives us an opportunity to find out why that happened at the weekend. The cold facts are that we've leaked 188 points in the last four games - you can't chase that."
Co-captains Sherwin and Guttenbeil (calf) were both receiving treatment this week in an attempt to make the Bulls clash on May 18.
Anthony Thackeray is not now going out on loan it has emerged, contrary to newspaper reports published late last week.
The ex-Hull FC half-back was rumoured to be joining Halifax to get much-needed game-time but no deal was agreed and Thackeray is back training at the Jungle.
Meanwhile, Castleford officials are so embarrassed by the surrender against Wakefield that they will give fans a refund. In an 'unreserved apology' to the Tigers faithful, the club offered to partially reimburse those supporters who made the trip.
Chief executive Richard Wright said: "There can be no excuses. The players are well paid and well looked after. With that comes a responsibility to give their all every week and to have nothing left in the tank at the end of every game.
"As a result, we are planning to offer those fans who bought their tickets from the club a reduction in the price of Tigers home tickets or merchandise to the value of 50 per cent of their Millennium ticket price. We hope that in some small way this move offers a little compensation to those who travelled down to Wales and deserved better than what was on offer from their team."