Lynn's four-game unbeaten league run was halted by two second-half goals at The Meres on Tuesday night.
Jamie McGhee sliced his volley past the Lynn near post on 20 minutes and Ash Burbeary rocketed his over the bar five minutes later.
Gary Mills's 29th minute long free kick bounced just too high for Jake Jones to connect and Grantham keeper Jake Turner snaffled the ball.
The Linnets enjoyed a strong spell in the final so minutes of the half. Jake Jones's shot was deflected wide, as was Richard Bunting's effort, and Turner got his fingertips to Andrew Hall's cross-cum-shot.
Turner was quickest to the ball to deny Sam Mulready on 40 minutes, and Dan Jacob just knocked wide from Hall's corner kick a minute later.
Greg Smith dragged his second half opening minute effort wide ofthe target, but he would prove to be the undoing of Lynn in the 55th minute.
From a long Adie Hawes throw, the ball eventually found Jamie McGhee who put in a cross through the six-yard box where Smith got a touch and the ball rolled slowly over the line.
The goal changed the whole complexion of the game and Lynn's Dan Quigley almost
rocketed the ball into his own net eight minutes later.
AcomposedSmithdoubled the Gingerbreads' lead in the 74th minute, controlling a through ball before firing past Lynn stopper Alex Street. Hall fired over the Grantham goal two minutes later.
As the final minutes ticked away, Jacob's desperate 25-yarder flew over the bar in his final appearance for the club.
|Grantham Town: Turner, Purcicoe, Andrew, Meikles (Hawes, 33), Miller,Towey, Burbeary, Nwadike, G. Smith, Fairclough (Jackson, 64), McGhee (King, 78). Subs not used: Graham, Lewis.
King's Lynn Town: Street, Thomson, Jacob, Lee, Fryatt, Bunting (Greg Mills 78), Hall, Gary Mills (Young, 65), Quigley, Mulready (Duffy, 65), Jones. Subs not used: R. Clarke. E. Clarke.