The striker has endured a difficult few weeks on and off the pitch but, back in the starting XI, he added a well-worked second to help seal a vital victory after record-signing Brown Ideye had opened the scoring on the hour mark.
Ideye’s strike was his second in as many games after almost leaving the club on deadline day, but Tony Pulis will be pleased the Nigerian stayed put if he continues this form.
Pulis, who has tasted defeat only once since taking charge at The Hawthorns, sees his men climb to 14th – four points clear of the drop zone – while a Swansea side who rarely threatened stay ninth.
All eyes were on Berahino on his return to the side after talking up his hopes of sealing a move to a “bigger club”, but he had a quiet opening half.
The best chance of the first 45 minutes fell to Gareth McAuley, but his flicked header was brilliantly saved by Swansea ‘keeper Lukasz Fabianski, who even had the awareness to clear the loose ball with his feet.
Bafetimbi Gomis had a rare sight of goal for the visitors, but blazed over after superb work from Jefferson Montero down the left wing.
After the break, the Baggies’ front men really stepped up their game, and combined twice to devastating effect.
First, Berahino was picked out by impressive substitute Stephane Sessegnon. The young striker scampered towards the area and slipped in Ideye, who wriggled free of Ashley Williams.
The defender recovered to block Ideye’s first effort only for the striker to clinically fire the loose ball into the bottom corner.
And Ideye repaid the favour 14 minutes later when Berahino made it 2-0.
The England Under-21 international received the ball in midfield, swapped passes with his strike partner and rifled into the top corner from 15 yards.
Swansea never recovered and Gomis nodded well wide with four minutes left to sum up their evening.
West Brom: Foster (7),Dawson (6), McAuley (8), Lescott (7); Brunt (5); McManaman (7), Fletcher (7), Yacob (6), Morrison (6), Ideye (8), Berahino (7).
Subs used: Sessegnon (7), Gardner (6).
Swansea: Fabianski (6), Naughton (6), Williams (7), Fernandez (5), Taylor (7), Ki (6), Cork (5), Dyer (5), Shelvey (6), Montero (7), Gomis (6).
Subs used: Oliveira (6), Routledge (5).
Man of the Match: Brown Ideye (West Brom).
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