Halifax teed up a Championship showdown with Featherstone next weekend potentially worth £250,000 to the winners with a dramatic victory in Wrexham.
Wing Gareth Potts was the visitors’ matchwinner, pouncing on a Callum Casey kick to put Halifax in front for the first time in the game just minutes from the end.
Karl Harrison’s side, who trailed 16-6 at half time, leapfrogged arch rivals Rovers into second place on the league ladder ahead of next Sunday’s meeting between the teams at the Shay.
With just three rounds remaining, the winners of next week’s game will be in the box seat to claim second and a £450,000 prize pot, with the third-placed club getting just £200,000.
The visitors made an awful start when Crusaders’ centre Greg Wilde sliced through to touch down on the right. And things went from bad to worse when the Crusaders scored again through Chrisiaan Roets on the other flank, Tommy Johnson converting the first for a 10-0 lead.
Halifax eventually composed themselves sufficiently for Ryan Fieldhouse to send Steve Tyrer stretching over, with the centre making it 10-6 with a conversion.
Former Halifax hooker Karl Ashall scored, Johnson converting for a 16-6 lead, but the visitors built some momentum after the break, Callum Casey scoring in the corner and Tyrer kicked the conversion for a 16-10 deficit.
A great finish from Luke Ambler then allowed Tyrer to level at 16-16 with 20 minutes remaining.
The visitors lost Tommy Saxton to the sin bin as the tension mounted, and Fax fell behind again when Jamie Dallimore’s drop goal put the Welsh side 17-16 up.
But when the home team spilled the ball in the final minutes, Casey kicked long towards the right corner and Potts did the rest.
North Wales Crusaders: Johnson; Turner, Wilde, Roets, Massam; Speakman, Dallimore; Martins, K. Ashall, Adamson, Gee, Wild, Middlehurst. Substitutes: Fildes, Smith, Reid, Duffy.
Halifax: Fieldhouse; Potts, Cowling, Tyrer, Saxton; Murrell, Johnston; Tonks, Kaye, Ambler, Robinson, Divorty, Adamson. Substitutes: Brooks, Holden, Casey, Spencer
Referee: T Crashley (RFL).