Hull FC trio Jacob Miller, Liam Colbon and Liam Watts failed to help Doncaster avoid defeat at Dewsbury after the Dons suffered a 24-8 defeat.
Watts, who failed to make the trip to Catalan Dragons after losing his passport, scored the only try for Paul Cooke's side in the 65th minute.
Former Hull star Anthony Thackeray did most of the damage for Glenn Morrison's men, with Kyle Briggs, Dale Morton, Callan Becket and Shane Grady sauntering in to rub salt in the wounds.
Rams substitute Rob Spicer spent ten minutes in the sin-bin for a late shoulder, and although Watts gave the Dons hope after crashing over from a scrum ten metres out, they couldn't maximise their numerical advantage.
The icing on the cake fell to ex-Hull KR favourite Makali Aizue, who powered his way up field to lay the platform for Thackeray to have the final word and ensured Doncaster's fine unbeaten run of four games came to a shuddering halt.
