The win moved Rangers (4-9-3), despite their poor record, to within two points of Detroit for fourth place and a playoff spot.
Maple Leafs (8-6-2) remain in third place, three points behind Boston.
Larry Popein's goal at 4:15 of the third period put Rangers ahead, 4-1, but Maple Leafs got a goal from Tim Horton about three minutes later.
Maple Leafs frantically pressured New York goalie Gump Worsley, but couldn't score again until 34 seconds remained, when Billy Harris deflected a shot by Bob Pulford past Worsley.
Prentice's wrist shot from the left faceoff circle found its way over Ed Chadwick's right arm at 1:40 of the third period. Prentice, expected to be a major goal scorer for Rangers this season, needed 16 games to tally his first.
A key moment came in the first period, when Rangers managed to kill off a five-minute major penalty incurred by Harry Howell at 8:39. That kept New York ahead, 1-0, thanks to Larry Cahan's power play goal at 7:10.
Neither team had a lot of shots on goal, but both clubs made the most of their opportunities. Toronto managed just 22 shots on goal while Rangers had 19. An astonishing 17 Toronto shots at the net were blocked, many by Howell. Rangers had just two shots on goal in the second period, but one of them eluded Chadwick---Parker MacDonald's deflection at 15:03.
1st Period
NY- Cahan (Prentice, Bathgate) PPG 7:10
2nd Period
TOR- Duff (Migay) PPG 9:42
NY- MacDonald (Hebenton, Lewicki) 15:03
3rd Period
NY- Prentice (Creighton, Bathgate) 1:40
NY- Popein (Foley, Howell) 4:15
TOR- Horton (Cullen, MacNeil) 7:31
TOR- Harris (Pulford, Cullen) 19:26
SOG
TOR 6-7-9 = 22
NY 8-2-9 = 19
PP: TOR 1-7; NY 1-4
Goalies
TOR- Chadwick
NY- Worsley
Prentice finally scored a goal in Rangers' win