Jersey threw away a 17-0 lead as they conceded a stoppage-time penalty try to draw 17-17 with Doncaster.
The islanders went ahead on 26 minutes as they forced a penalty try after Doncaster brought down their maul.
Gary Graham's push-over try and Brendan Cope's penalty put Jersey 17-0 ahead at half time.
Doug Flockhart's 72nd minute penalty gave Knights hope before former Jersey forward Latu Makaafi went over and Doncaster forced the late leveller.
The Knights opted to kick a stoppage-time penalty to touch and their maul from the resulting lineout was pulled down by Uili Kolo'ofa'i leaving the referee to award the penalty try and Flockhart to kick the conversion to seal the draw.
The draw sees Jersey move up to fifth in the Championship as they leapfrog Nottingham after they lost to leaders Bristol, while Doncaster stay in second place.
Jersey: Lane; Howe, Otto, Robling, Adair; Cope, Moates; Lockwood, Selway, Tomaszczyk, Phillips, Rowlands, Graham, Freeman, Rae (capt)
Replacements: Lancuba, Garcia-Veiga, Herriott, Kolo'ofa'i, Spinks, Dudley, McCrea
Doncaster: Jarvis; Flockhart, Clark, Hurell, Lewis; Cusack, Heaney; List, Hunter, Quigley, Phelan, Challinor, Shaw, Hills, Stedman
Replacements: Sproston, John, Veikoso, Hotson, Makaafi, Edgerley, Humberstone