They now must hope Down beat Meath tomorrow to avoid a relegation scrap.
Westmeath's full forward line managed 2-9 but it wasn't enough to stop them succumbing to a three point defeat to Mayo, 2-12 to 0-21 the final score.
It all began brightly with a Luke Loughlin goal on two minutes but last year's All-Ireland finalists quickly stamped their authority on the game kicking six of the next seven scores.
Not to be out pointed the lake county roared back themselves and when John Heslin converted a penalty on 27 minutes to give them a two point lead, an upset was on the cards.
It was an advantage that Westmeath would not relinquish until a Cillian O'Connor free in the 51st minute but from then on Mayo never looked back.
The teams traded scores and the Connacht side never built more than a three point lead but Westmeath's concession of frees at crucial times would prove costly.
Five of Mayo's eleven white flags in the second period were from placed balls.
A penny for Jack Cooney's thoughts heading into the final weekend of the National League against Down. In other circumstances his team could be two from two and staring promotion in the face.
Instead in all likelihood they will be facing Laois or Clare in a relegation contest when the group phase is over.