Stephane Sessegnon scored against his former club on his West Brom debut to set the Baggies on course for their first win of the season.
Sessegnon opened the scoring on 20 minutes and Liam Ridgewell doubled the lead 14 minutes from full-time to confirm a huge victory for Steve Clarke’s side.
And Morgan Amalfitano capped a man-of-the-match display when he added the third goal in stoppage time.
It was a much-improved display by Clarke’s men, albeit against a dismal Black Cats side, with several summer signings to the fore including the previously subdued Nicolas Anelka.
Albion had an early half-chance when Sunderland keeper Keiren Westwood misjudged a hopeful forward ball and ended up meeting it outside his penalty area.
Nicolas Anelka closed him down and got a foot to the ball but it rebounded nicely for Westwood to gather just inside the box.
After a bright start by Albion, Sunderland enjoyed a spell of pressure that the Baggies were forced to survive.
But it was the home side who went ahead on 20 minutes when three of their late-summer recruits combined.
A cross from the right by Amalfitano was turned goalwards by Scott Sinclair, who was restored to the starting line-up in place of the injured Chris Brunt.
Westwood parried Sinclair’s shot but only into the path of Sessegnon, who forced it home.
It could have been 2-0 for the Baggies midway through the half when Anelka combined cleverly with Morrison to tee up Amalfitano, whose left-footed shot deflected off Modibo Diakite and clipped the crossbar on its way out for a corner.
And Anelka, who produced a lively first-half display, burst down the right moments later and tried to pick out Sinclair but Westwood gathered comfortably.
Albion made a sluggish start to the second half, allowing Sunderland to exert some early pressure.
But the Baggies rediscovered some of their first-half tempo and Sessegnon went close to adding his second on the hour-mark.
He turned smartly away from Diakite and let fly with a dipping right-footed shot but it curled wide of the far post.
The visitors appealed for a penalty when they opened the Baggies up with some neat passing and substitute Jozy Altidore claimed his shot had struck Jonas Olsson’s arm.
But referee Phil Dowd awarded a corner.
Sunderland could have drawn level when a fine cross by Adam Johnson found Steven Fletcher but the former Wolves man fired over while being tackled by Billy Jones.
A heavy landing ended Fletcher’s afternoon and left Sunderland, who had already used three substitutes, down to 10 men for the end of the game.
And Albion cashed in when they doubled their lead.
Amalfitano was again the creator with a fine cross that Westwood could only claw away as far as Ridgewell, who steamed in to finish.
And Amalfitano could have added a goal to his impressive performance when he got on the end of a neat move but he attempted to pick out Victor Anichebe instead of shooting and the chance went begging.
He did find the net in stoppage time, however, when he collected an excellent lay-off from Anichebe and drilled a shot past Westwood.
By Steve Madeley