The Giants are a point in front of Warrington and need to win one of their last two matches to secure the league leaders' shield for the first time.
They would already be celebrating had St Helens, coached by former Huddersfield boss Nathan Brown, managed to beat the Wolves on Friday night, but Crabtree is confident his side will not freeze on the big occasion.
"We can't go into this game thinking it's a Grand Final or anything," he said. "It would be another step closer to one of the many things we want to achieve at the club.
"We don't want to slip up now."
The leaders' shield has been denigrated by coaches and players alike who have their sights set on the bigger prize at Old Trafford but Crabtree insists his club would treasure it.
"I would have agreed with them but when you've won absolutely nothing, it's a pretty big deal," he said.
"It proves how good we have been and how far we've come. I'm really impressed and happy that this season we've competed all the way through.
"We're still waiting to taper off but the press seem to have stopped asking us about it which is quite amusing.
"I'm the only player who's been relegated and promoted, going from the basement right to the top, and it's pretty big for me.
"I'm really happy with the fact I decided to stay here until I win something and this puts me a step closer. I can probably retire at some point and look back and realise I actually did something."
Elsewhere on Sunday, Hull KR go to Widnes in a game that features the teams who pulled off major shocks in the last round.
Rovers, who toppled champions Leeds at Headingley a fortnight ago, need a win to keep alive their hopes of a home tie in the play-offs, while Widnes, with vivid memories of their stunning derby win at Warrington, have a target of their own to aim for.
Widnes coach Denis Betts said: "For us it is about finishing on a high and reaching the 20-point target we set at the start of the year.
"A total of 26 points has made the cut for top eight this season so we weren't that far away from mounting a challenge ourselves for those positions."
Castleford's incentive for the last two rounds is to finish above rivals Wakefield, their opponents in their final game next Sunday, but first they must see off Salford at Wheldon Road.
The match is expected to be the last at home for Rangi Chase, who last week submitted a transfer request and is expected to be unveiled as a Salford player next Thursday.
Adding extra spice will be the appearance in the Reds squad of stand-off Marc Sneyd, who is set to move to Castleford in exchange for Chase, and centre Ashley Gibson, who has already confirmed a switch on a two-year deal from 2014.
London Broncos will be condemned to the wooden spoon if they fail to halt a 12-match run without a win when they visit Bradford.
The Bulls can finish no higher than ninth but coach Francis Cummins insists there is still plenty to play for on the first anniversary of the club's takeover by Omar Khan.
"It's about personal pride now," Cummins said. "We want to finish off for our supporters who have been tremendous all year.
"They have had some good things to cheer about and some good performances from us this year and we want to go out with a couple more."