Stand-in Newcastle goalkeeper Karl Darlow had a Premier League debut to forget as his error handed West Brom a 1-0 win.
Darlow was brought in as a late replacement for first-choice Rob Elliot, who was unwell in the warm-up, but he allowed a Darren Fletcher header to squirm past him with 12 minutes remaining.
A high-intensity encounter saw woodwork hit three times - once by the Baggies and twice from Newcastle - while West Brom forced 17 corners and had 22 shots at the Newcastle goal - 12 of which were blocked by some magnificent last-ditch defending.
The victory ends a run of five games without a win for Tony Pulis' men, who pull six points clear of relegation threatened Newcastle.
But Steve McClaren's men, who had appeals for a penalty on Aleksandar Mitrovic turned down, remain in the bottom three.
West Brom were keen to put pressure on Darlow, who has made just one appearance for Newcastle - in the Capital One Cup - since moving from Nottingham Forest in 2014.
Victor Anichebe - starting ahead of the out-of-favour Saido Berahino, whom Tony Pulis said was "lucky to even be on the bench" - caused havoc in the penalty area but though the ball broke to James Morrison six yards out, his effort was blocked on the line by Fabricio Coloccini.
Morrison fired another effort at goal six minutes later from 20 yards which was diverted away to safety by the alert Darlow.
That should have settled his nerves, but he rarely looked comfortable when the pressure was turned up.
Georginio Wijnaldum was a threat on the counter attack for the visitors and he stung the palms of Boaz Myhill on 13 minutes in a breathless first quarter of the game.
The pace did ease but Coloccini's level of performance did not as he was perfectly positioned on 28 minutes to block a Fletcher attempt away from inside his own six yard box, before making another vital intervention from under his own crossbar following a looping Jonny Evans header.
Newcastle threatened themselves from set-pieces and somehow failed to take the lead on 55 minutes.
Paul Dummett rose highest from a left-wing corner and his header looped towards goal but came back off the woodwork. The ball then dropped to Coloccini around six yards out but his back-heel clipped the post and went wide.
The visitors continued to press and had claims for a penalty on 61 minutes.
Mitrovic bundled his way past Evans inside the box, who had his arms all over the striker. The Newcastle man managed to get his shot away, which was cleared by Chris Brunt, but he felt he was impeded by the Baggies man. The referee was unmoved.
Newcastle substitute Cheick Tiote, who replaced the hamstring-stricken Vurnon Anita, sold Darlow short with a back-pass on 71 minutes but Anichebe could not flick his effort into the unguarded net.
The burly striker came even closer four minutes later, winning a header inside the six-yard box following a Brunt corner but the ball rebounded back off the crossbar.
The pressure was growing on Darlow, who had looked nervous throughout - flapping and spilling crosses - and with 12 minutes to go, his mistake handed West Brom the three points.
Fletcher burst into the box and met a Claudio Yacob cross with a firm header. The ball was straight at the goalkeeper but he failed to get any weight behind the effort and it squirmed agonisingly into the back of the net.
Darlow did redeem himself slightly in the closing stages with two good stops from substitute Berahino and Anichebe, but the damage had already been done.
Newcastle failed to muster a single chance in the closing 10 minutes. A turbulent 2016 may await the Toon.
Charlie Nicholas's Soccer Saturday verdict
"(Newcastle) gave everything they had, and were pretty decent going forward at times. Defensively, they put their bodies on line.
"At one point in the second half they had a stonewall penalty (Evans on Mitrovic). It was like a challenge from 10 years ago - I don't know how he got away with it.
"Steve McClaren will be pleased with the effort, they gave everything. Paul Dummett was unlucky after hitting the bar - he had an excellent game - but there was justice in that West Brom won the match.
"Berahino came on, and looks as if he needs games. He might have to trim up a bit. I don't see him being there much longer - and by the time we do our next show, I'd be surprised if we're not talking about where he will be next."
Player ratings
West Brom: Myhill (7), Olsson (6), Yacob (7), Evans (6), Morrison (6), Anichebe (8), Brunt (6), McAuley (7), Fletcher (8), Dawson (7), Sessegnon (7).
Subs used: Gardner (6), Lambert (6), Berahino (6)
Newcastle: Darlow (4), Janmaat (7), Mbemba (6), Coloccini (7), Dummett (6), Sissoko (6), Colback (6), Anita (6), Wijnaldum (6), Mitrovic (6), Perez (6)
Subs used: Tiote (6), Thauvin (6), De Jong (6)
Man of the match: Victor Anichebe