Clive Griffiths' side, now second in the Championship after Yorkshire Carnegie slipped up against London Welsh last night, might have expected a simple ride versus the strugglers.
However, they were 8-7 behind at half-time and had to battle all the way in a scrappy rain-drenched encounter.
For all they enjoyed the majority of possession and territory, the South Yorkshire club failed to really convince and it was not until Latu Makaafi scored in the 68th minutue with his first touch after coming on, that they truly secured their seventh league win of the campaign.
That was the flanker's 12th league try of the season as he stayed to of the Championship's scorer's list.
Crucially, the hosts went on to bag a bonus point, too, when full-back Paul Jarvis crossed in the final minute, Dougie Flockhart converting from the touchline to finish with a personal haul of 14 points.
Tyson Lewis had regained Doncaster the lead after a fine David Clark break in the 47th minute, No8 Ollie Stedman having crossed in the first half from a line-out drive, as the Knights backed up their last league fixture, the impressive win at leaders Bristol.
Doncaster Knights: Jarvis; Flockhart, Clark (Bulumakau 79), Hurrell, Lewis; Cusack, Heaney (Edgerley 77); List (Bergmanas 71), Hunter (Viekoso 67), Quigley (Johnn 67), Challinor, Phelan, Shaw (Makaafi 67), Hills, Stedman.
Moseley: Foley; Williams (Armstrong 47), King, Pinches, Cheshire; Hughes, Brown (Brazier 65); Fiddler (Warren 65), Caves, Voisey (Gardiner 65), Flagg, Charlton, Lawrence, Siggery, Brightwell.
Referee: Andrew Jackson