Dewsbury Rams were leading 12-10 some 13 minutes into the second half after a rousing performance against a Bulls side featuring half a dozen first-teamers.
Dewsbury Rams 12
Bradford Bulls 46
However, the balance of play quickly swung Bradford's way when Dewsbury coach Warren Jowitt replaced his frontline players to blood his rookies.
Prop Anthony England gave the Rams the perfect start, touching down a grubber kick by ex-Bulls hooker Johnny Horton in the 11th minute.
Patrick Walker converted to give the home side a 6-0 advantage.
Bradford hit back with a burrowing try from new star signing Matt Diskin, goaled by another high-profile acquisition, ex-New Zealand Warrior Patrick Ah Van.
The game ebbed and flowed – with errors but excitement – and Dewsbury re-took the lead in the 43rd minute when slick passing allowed full-back James Craven to tear through a gap to score, Walker converting for 12-6.
AhVan crashed over six minutes later as Bulls pulled back to 12-10 but then Jowitt made wholesale changes – amazingly almost 60 players got a run-out between the two sides.
With their forwards a stone heavier and their backs a yard faster the Bulls rattled up 36 unanswered points. Kyle Briggs and Cain Southerwood ran the show for the Bulls from then on and tries came at regular intervals for Liam Mackay, Vinny Finnigan (2), Lewis Reed, Steve Crossley and Michael Platt, with AhVan taking his tally to seven goals.
The game was watched by 1,600 and the gate receipts go to the host club, bringing much-needed revenue before the start of the season proper with a trip to Toulouse on February 5.
Dewsbury Rams: Craven, Wainwright, Faal, Glynn, Turner, P Walker, Brambani, England, Horton, Hirst, Cosgrove, Spicer, Roberts. Subs (all used): Lockwood, Tonks, Menzies, Hayes, Wandless, Brooks, Bibb, Wright, Binks, Saxton, D Glassell, Shaw, Flowers, S Glassell, Emblem, J Walker, Wilson, Wall, Tebb, Cawthorn.
Bradford Bulls: Ah Van, Finnigan, Platt, Sykes, Crookes, Briggs, Southernwood, Scruton, Diskin, Kopczak, Elima, Whitehead, Addy. Subs (all used): Windler, Burgess, Reed, O'Brien, Mackay, Crossley, Murphy, McAvoy, Bateman, Hawthorne, Olbison.
Referee: T Roby