Alex Walmsley says Saints are a different side to the one that faced Castleford in mid-June.
They were edged 16-12 in a clash they dominated at the Mend-a-Hose Jungle… but failed to finish off.
“It was frustrating the last time we played them because we went against our principles at key times of the game,” he explained. “For the first time in a while we struggled putting it to bed. We have to learn from that and we are a different team from six weeks ago.
“We have got used to Justin’s structure and are playing his style a little better. I think we were lacking a strict approach to our game; we were wayward in how we were playing. But he has stripped everything back and we are building on it week on week.
“In the pack we complement each other and that approach is favouring us. We are being physical too and that is important. Luke Thompson has come in and been outstanding for us over the last few weeks. He has been a big player and is reaping the rewards off the back of that.
“We got an overdue away win at Wakefield but we cannot afford to slack off now. Cas are the best team in the comp and it will be a tough game.”
Saints lie sixth in the table – just a point behind the top four – and their destiny is in their own hands.
Win their Super 8 games and a playoff place is secured.
“We’re not here to make up the numbers; we are here to win it but that is a long way off at the moment,” he added. “Initially, we want to get into the top four and then get back to Old Trafford and win it.
“You don’t come here to be a team that makes up the numbers. You come here to win trophies. We are a little behind on the scoreboard but our destiny is in our own hands.
“If we win seven games we are back in the semis.”