SAIDO Berahino showed nerves of steel late on to get 2014 off to a flier for Albion with their first win in ten games.
The Baggies looked to be heading for a fourth successive draw as they wasted golden opportunities to score against ten-man Newcastle.
Nicolas Anelka fired a great chance over a minute before the break and Liam Ridgewell missed an open net in the 83rd minute.
In between, Mathieu Debuchy was sent-off on 62 for a reckless challenge on Claudio Yacob.
And Keith Downing enjoyed his first victory as caretaker boss thanks to Berahino’s 87th-minute penalty – his fourth Barclays Premier League strike of the season and second in as many games.
The Albion line-up saw three changes, with Yacob, Morgan Amalfitano and Stephane Sessegnon earning recalls.
Alan Pardew brought back Shola Ameobi as the only change to the Magpies’ XI.
Before kick-off, a minute's applause was observed in honour of former chairman and president John Silk LLB, who passed away, aged 89, yesterday.
Both sides jostled for territory early on but it was the hosts who threatened first.
In the sixth minute, Anelka’s attempted cross from the right clipped off the heels of Fabricio Coloccini to Amalfitano, whose 18-yard shot on the turn was easy for Tim Krul to deal with.
Amalfitano was in the action again on 12 as he nut-megged Davide Santon down the right and delivered a cross into the middle that Krul just grabbed before it dropped under the crossbar.
Mike Williamson got a goal-saving touch on Liam Ridgewell’s left-wing cross in the 16th minute. The United centre-half slid in to get a toe to the ball and take it just out of the reach of Sessegnon in the six-yard box.
Billy Jones needed treatment to a cut eye on 23 as Ben Foster came rushing off his goalline to punch clear Loic Remy’s lofted ball towards Yoan Gouffran – but also caught the Baggies right-back in the face with his arm.
The visitors created a good opening four minutes later as Williamson headed down Mathieu Debuchy’s cross and Yohan Cabaye volleyed just wide of the left-hand post from ten yards, with the goal at his mercy.
Moments later, Jonas Olsson got above Williamson from Amalfitano’s in-swinging corner and headed just wide of the back post.
Amalfitano played a neat one-two with Sessegnon on the right wing on the half-hour mark and centred for Brunt, who was unable to direct his header on target from eight yards.
A minute before the break, the Baggies should have taken the lead. Amalfitano showed good strength and skill to get past Gouffran in the box and pull the ball back from the right byline. Anelka pipped Coloccini to the ball in the six-yard box, only to fire over.
Downing was forced into a change at the break as Jones went off and Berahino came on. Amalfitano dropped into defence to fill in at right-back. The Magpies also made a switch as Hatem Ben Arfa replaced Gouffran in midfield.
Cheick Tiote fired in an ambitious 25-yard volley ten minutes into the second half, which Foster was glad to clutch as it skipped up off the turf.
Two minutes later, Brunt found Berahino just inside the box and he was unfortunate to see his goalbound strike hit Williamson.
A swift counter-attack then saw Moussa Sissoko’s pass pick out Remy in the penalty area and he brought the ball down before curling a shot just past the right-hand angle of post and bar.
The visitors were reduced to ten men in the 62nd minute as Debuchy was given his marching orders for leaving the floor with a two-footed challenge on Yacob.
Brunt slid the resultant free-kick down the left side of the box for Berahino, who shot wide of the near post.
Seconds later, Mapou Yanga-Mbiwa replaced Coloccini in central defence, while Sissoko slotted in at right-back.
Anelka picked up a loose ball on 69 and fired in a low 20-yard shot that Krul dived to his right to smother.
Sessegnon powered into the box on 74 and was kept out by Krul blocking at his feet.
Moments later, Anelka slid Berahino in down the left and his cheeky effort from 15 yards was just stopped by Krul at the base of his right-hand post.
Pardew brought on Massadio Haidara for Shola Ameobi in the 76th minute and a minute later Downing followed suit by bringing on Matej Vydra for Sessegnon.
The Baggies should have been in front in the 83rd minute as Berahino latched onto Brunt’s exquisite reverse pass and slid the ball into the six-yard box, only for Ridgewell to somehow fire wide when it seemed easier to score.
The hosts persisted, though, and won a penalty when Vydra chased onto Brunt’s pass and was tripped by Krul.
Berahino stepped up and kept his cool to slot the ball home in the bottom right-hand corner and give the Baggies the lead with three minutes to go. That proved enough for the Baggies to secure an overdue and thoroughly-deserved win.
ALBION (4-4-1-1): Foster; Jones (Berahino HT), McAuley, Olsson, Ridgewell; Amalfitano, Mulumbu, Yacob, Brunt(c); Sessegnon (Vydra 77); Anelka (Gera 88). Subs not used: Myhill (gk), Morrison, Long, Lugano.
NEWCASTLE (4-3-3): Krul; Debuchy, Coloccini (c) (Yanga-Mbiwa 65), Williamson, Santon; Cabaye, Tiote, Sissoko; Remy, Shola Ameobi (Haidara 76), Gouffran (Ben Arfa HT). Subs not used: Elliot (gk), S Taylor, Anita, Cisse.
GOALS: ALBION – Berahino (pen 87).
SENDING-OFF: NEWCASTLE – Debuchy (dangerous play 62).
REFEREE: L Mason (Lancashire).
ALBION STARMAN: Morgan Amalfitano.