Shane Long scored the opener for the visitors shortly after halftime but Paul Lambert's men came back to share the spoils and move into 15th place in the Premier League.
Both teams cancelled each other out in a scrappy opening period but the contest came alive after the break as Paul Lambert's side fought back after the visiting team got its nose in front.
The recalled Gabriel Agbonlahor looked eager from the start to continue the form he showed at during the week and he almost cut open the Baggies rearguard with a darting run and a whipped cross that was just beyond the prowling Christian Benteke.
Villa gradually took a foothold in midfield and Australian winger Brett Holman was finding plenty of space in front of the Baggies box. Foster had to look lively to tip Holman's 30-yard thunderbolt just over the bar and shortly later the Aussie screwed another effort wide of the target after good work from Agbonlahor.
Baggies skipper Chris Brunt went down clutching his left hamstring and while he hobbled off Ciaran Clark rose to head an Agbonlahor cross just wide.
Brunt was replaced by Graham Dorrans, but while West Brom was still reorganizing, Holman out-muscled Gareth McAuley and saw his deflected effort tipped wide.
Steve Clarke's troops were desperate for the halftime whistle and their cause wasn't helped when Billy Jones went down clutching his right knee and was replaced by Gabriel Tamas a minute before the break.
The Baggies were on the ropes, but they came out after the break intent on giving as good as they got.
They gave a warning of what was to come when Shane Long's header was ruled offside. Villa didn't heed the warning and in 51 minutes the club was punished when Morrison beat the offside trap to send in a cross that Vlaarcould only divert into the path of Long who scored from close range.
Villa recovered from this setback and piled forward. Benteke was wasteful with a couple of opportunities and Lowton saw a 30-yard curler go just over the bar.
Paul Lambert made three substitutions in two minutes and two of them were involved in the leveler on 80 minutes.
With 10 minutes to go, a Barry Bannan cross was headed on by Vlaar and then Clark's volley was blocked only for Bent to bundle the ball home.
In a grandstand finish, Bent almost claimed the points for Villa but he scooped a 20-yard effort just wide.
The Baggies emerged from being under the cosh almost to grab the spoils but Romelu Lukaku's angled drive was blocked by Guzan.
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