Knights can finish no higher than sixth in the Championship after a resounding defeat at Meadow Lane.
Both Nottingham and Doncaster took the opportunity to rotate their squads for last night’s rearranged fixture having already secured their place in the promotion play-offs - where they could yet meet again.
But it was the home side’s fringe men who dominated proceedings and ran in five tries to Knights’ two.
Matty Williams’ early score, and skipper Steve Lawrie’s second half try, kept the Knights in contention despite Nottingham enjoying the greater share of possession.
But the hosts led 16-10 at the break thanks to tries from Craig Hammond and Sione Kalamafoni before Chris Eggleshaw crashed over out wide to extend their lead ten minutes after the restart.
Lawrie briefly raised hopes of a comeback when he was credited with the score as Doncaster drove home a 10-yard maul.
Nottingham, however, finished the stronger of the two sides and gave the scoreline an emphatic look as Tim Streather broke clear in the closing stages before Kalamafoni crossed the line in stoppage time for his second score of the game.
Knights welcome Esher to Castle Park on Saturday (2.30pm).