A 76th minute free from John Heslin was enough to give side a crucial victory over Clare, after a tight, tense game of football in TEG Cusack Park.
It was not a classic by any stretch of the imagination, but Westmeath will care little with so much at stake, as the teams relegated could be facing the prospect of playing in a tier two championship.
Clare will be very disappointed by the manner of this defeat, as they looked set to have stolen a draw, until Heslin stepped up to seal the victory.
Ray Connellan played his first game for Westmeath since 2016 and he was very impressive, setting up his sides, while scoring two points from play.
Westmeath opened the scoring with a free from John Heslin, which was quickly cancelled out by David Tubridy's place ball effort.
Clare then got the games first goal in the 6th minute, which came courtesy of Gavin Cooney, after Dermot Coughlan’s initial effort was blocked.
Tubridy scored his second free in the 8th minute to stretch his sides lead to four, but Clare would not score for another 27 minutes, as Westmeath registered 1-3 in the interim period.
A free from Heslin left three between the teams, before Jack Cooney’s side found the net in the 16th minute, as Anthony McGivney found the target, after a great piece of play from Ray Connellan.
Points from Connellan and Callum McCormack left two between the sides, before Tubridy scored his third free on the stroke of half time.
Kevin Maguire scored a point in stoppage time, but Clare were dealt a major blow when Dermot Coughlan was shown a black card and sent to the sin-bin following a foul on Ronan O’Toole.
Westmeath held a 1-5 to 1-3 lead at the interval, after what was a poor first half from a spectators' point of view.
Westmeath started the second half superbly, with points from Lorcan Dolan and Heslin giving them a four-point lead.
Clare responded with two points in succession to halve the deficit, before Jack Smith scored a crucial goal in the 49th minute, to give his side a five-point lead.
Tubridy replied with two frees, before a Ray Connellan free settled Westmeath, though Clare responded with three successive scores to leave just one between the sides.
Killian Daly and Alan Sweeney were both shown straight red cards in the 70th minute, before a Dermot Coughlan score levelled the game deep into additional time.
Cooney’s side prevailed by the skin of their teeth however as Heslin landed his late free.
Westmeath now face Cavan away next weekend, while Clare are at home to Kildare.
Westmeath: Eoin Carberry; Jack Smith (1-0), Kevin Maguire (0-1), Boidu Sayeh; Killian Daly, Ronan Wallace, James Dolan; Denis Corroon, Ray Connellan (0-2); Anthony McGivney (1-0) (Conor Slevin 56), John Heslin (0-4, 0-3f), David Lynch (Conor Coughlan 68); Callum McCormack (0-1) (Thomas McDaniel 59), Ronan O’Toole, Lorcan Dolan (0-1) (Luke Loughlin 68).
Clare: Stephen Ryan; Kevin Harnett, Cillian Brennan, Gordon Kelly; Sean Collins (Eoin Collins 68), Pearse Lillis, Dean Ryan (Alan Sweeney 54); Ciaran Russell (Dale Masterson 74), Cathal O’Connor (Ciaran Downes 68); Cian O’Dea, Eoin Cleary (0-1), Dermot Coughlan (0-1); Gavin Cooney (1-0) (Cormac Murray 54), David Tubridy (0-8, 0-7f), Keelan Sexton (0-1).
Referee: Niall Cullen (Fermanagh)