In a tight first half, the sides were level five times with Callum McCormack very much to the fore for the Lake County, kicking over three fine points in the opening minutes.
Barry McKeon and Brian Kavanagh did the early scoring for Longford while a point from James McGivney gave them a slight edge at half-time, 0-6 to 0-5.
Longford completely dominated the early exchanges of the second half and points from Kavanagh (two frees) and substitute Robbie Smyth gave them a four-point lead in the 44th minute.
John Heslin replied with a free for Westmeath before Longford lost McGivney with a black card.
The lead was four again in the 50th minute after a fine sideline ball from Darren Gallagher found Michael Quinn and he pointed. Westmeath were in desperate need of scores and Heslin brought an excellent save out of Longford keeper Paddy Collum.
The sides then traded points but Longford were dealt a blow in the 61st minute when wing-back Diarmuid Masterson was sent off for a second yellow card. Westmeath tried to make use of their numerical advantage but Longford proved resilient, though Longford’s Robbie Smyth was black-carded too.
Heslin (free) and John Egan cut the deficit for Westmeath in stoppage time but that was as close as they got.
B Kavanagh (0-5, 4 frees): B McKeon 0-3 (2f), R Smyth 0-2, D Reynolds, M Quinn, J McGivney 0-1 each.
J Heslin 0-5 (4 frees), C McCormack (0-3); S Dempsey, P Greville, J Egan (0-1 each).
P Collum; D Masterson, B Gilleran, A Farrell; D McElligott, D Brady, D Reynolds; D Gallagher, M Quinn; B O’Farrell (F Battrim 54), J McGivney (bc M Hughes 48 (B Farrell bs 62), B McKeon (M Hughes 69) ; P McKeon (CP Smyth 63), B Kavanagh, L Connerton (R Smyth 32 (bc Shane Doyle 70+1).
D Quinn; K Daly, F Boyle, K Maguire; P Holloway, K Martin (P Greville 54), D Lynch (J Egan 53); D Corroon, D Daly (J Connellan ht); R Connellan, C McCormack, J Dolan; G Egan, J Heslin, S Dempsey.
N Cullen (Fermanagh)