Veteran midfielder Wrack seized upon Mark Bradley's wayward shot from outside the area to score his first of the season and leave under-pressure Bournemouth manager Kevin Bond without a home league win since March.
Bournemouth should have sealed all three points before Wrack's untimely intervention as they dominated throughout and took an early lead through the impressive Jo Kuffour.
The former Arsenal trainee was left with virtually an open goal on 20 minutes after Paul Telfer's cross had ricocheted off a number of defenders and he duly obliged by netting his fourth of the season.
The home side pressed on in desperate need of points to lift them off the foot of the table and, despite enjoying the lion's share of possession against a distinctly below-par Walsall outfit, never really troubled Clayton Ince.
Saddlers midfielder Michael Dobson went close just after the half-hour mark forcing Neil Moss into a smart low save, but that was as good as it got for the Midlands side as they appeared a team there for the taking.
The second half progressed much the same as the first as, despite Anthony Gerrard going close on 52 minutes, Bournemouth continued to dominate.
Kuffour should have sealed his second and surely all three points on 53 minutes as he was teed up by Adam Lallana and, despite having the goal at his mercy with no defender in sight, conspired to completely mis-kick and screw his shot horribly wide of the target.
Marc Wilson's positive run into the area 20 minutes later was curtailed just as the Northern Ireland Under-21 international was shaping to shoot.
Then, with an air of inevitability, Wrack t sealed a scarcely deserved away point, but in a frantic final two minutes, Bournemouth strikers Lee Bradbury and Sam Vokes both missed gilt-edged chances.