The Baggies had not won in four Premier League outings, drawing just one of them, but produced a turn of form to get out of their late season rut.
The home side took an early lead when Rovers defender Martin Olsson turned Gareth McAuley's header from a corner into his own net before Baggies on loan keeper Ben Foster came up with two huge saves to deny Yakubu and then Bradley Orr ten minutes into the second half.
Blackburn would have ben wondering how on earth they were not level and just over minutes from time would have been scratching their heads even more when Marc-Antoine Fortune fired home at the back post after Chris Brunt's rightwing cross found its way to the Frenchman.
With five minutes to go, West Brom went three ahead thanks to Liam Ridgewell's fine header from Graham Dorrans' free-kick for his first Baggies goal before things went from bad to worse for Rovers when substitute striker Anthony Modste was harshly sent off for a push on Billy Jones.
The defeat leaves Steve Kean's side in 18th position on the table and with plenty of work to do to avoid relegation whilst Roy Hodgson's Albion moved up to 12th with a timely victory.
TRIBAL ASKS: Is that it for Blackburn or do they have enough fight to keep themselves up?
The Hawthorns, West Bromwich - 23,414
Yellow cards:WBA - nil BLA - Scott Dann 51'
Red card:BLA - Anthony Modeste 89'