Castleford and Widnes aim to draw first blood on Thursday in their battle for a return to Super League.
The promotion front-runners meet in the Co-operative National League One qualifying semi-final at The Jungle with the winners going straight through to next month's Grand Final.
It is a likely rehearsal for the October 7 promotion decider, with the losers having a second chance to reach Headingley when they meet the winners of Sunday's elimination semi-final between Halifax and Whitehaven.
The Tigers have home advantage on Thursday but results between the teams this season have forced Castleford coach Terry Matterson to adopt a cautious approach.
"I'm not too sure how important it is," he said. "In the regular season, it hasn't been a bonus because they gave it to us at our place and we beat them over there.
"Our form has been good but we know this is a major test. Although you get another bite of the cherry I'm sure both Steve McCormack and myself will want to get the job done at the first possible opportunity."
McCormack has already guided the Vikings to victory in the Northern Rail Cup final but that will count for little if they fail to achieve their goal of promotion.
"We'd have preferred to have been top of the table - we're disappointed to have finished second," said McCormack.
"But the most important thing was that we finished in the top two because it gives you two bites at the play-offs.
"Going to Castleford is going to be a big challenge but we're looking forward to it.
"It's about who handles the pressure - I don't think there's a lot between the two teams. It's irrelevant what has happened earlier this season once you hit the play-offs."
McCormack is expecting to pick from a full-strength squad, with Toa Kohe-Love, Dennis Moran and Ian Webster added to the team that finished the regular season with victory at Batley.
Matterson has added Tere Glassie, Craig Huby and Ryan McGoldrick to his squad after they missed the Tigers' record 106-0 victory over Rochdale.
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