Rovers travel to face the Warriors on Friday (local time), with Australian coach Peters admitting his Super League side need to focus against Matt Peet's team.
Former South Sydney star Joe Burgess led the way for Peters' side against Castleford with a hat-trick as Rovers also crossed through Australian-born PNG representative Rhyse Martin, Jez Litten, Mikey Lewis and Arthur Mourgue, the latter also kicking four conversions.
Castleford's first-half try came courtesy of Alex Mellor. Daejarn Asi added the extras.
Win No.18 in Super League this season saw Rovers lift the Roger Millward Trophy to add to the Challenge Cup, but it is the League Leaders' Shield and a grand final triumph they covet most.
"Will that performance cut it next week? It won't. We will have two teams going at it next week," Peters said.
He admitted it was too early to call a win at Wigan a decider in the race for the League Leaders' Shield.
"I think there's too long to go,'' Peters said.
"When you've got Leigh playing the way they are, you've got St Helens and Leeds. Next week's important, it's Wigan and it's a big game."
He said his side had not hit top gear against Castleford.
"It was a weird game,'' Peters said. "I thought we did a lot of good things. We put a lot of pressure on them. Our defence was good for the majority of the game.
"What I did like there were a lot of good things which we did do. The points came at the back end because of what we did. I thought overall we defended well"
