Twice Newcastle came from behind to salvage a point, having gone into the game knowing victory would open a five-point lead at the top of the Championship.
Seven players were cautioned - five for the Baggies - in a match of sheer endeavour that ended with Baggies substitute Ishmael Miller missing an unbelievable chance to seal it for the Midlanders.
West Brom led first through big Swedish defender Jonas Olsson and Roman Bednar, before United hit back with a Danny Guthrie goal and another from Peter Lovenkrands.
It was a poignant moment for Lovenkrands, the Dane holding his hands to the sky in memory of his father who died three days ago.
It was the Baggies who started off the more brightly with Newcastle constantly troubled by their pace.
Yet it was United who created the first opening when Kevin Nolan and Shola Ameobi combined to set up Lovenkrands, who was a stride away from converting.
West Brom hit back and Graham Dorrans fired over before setting up the Baggies to become only the fifth team to score at St. James' Park this season.
Dorrans whipped in a cross from the left, but Ameobi must shoulder the blame as he switched off and allowed Olsson the chance to deflect the ball beyond Steve Harper.
This was only the second time United had trailed at home this season, but they were soon level with an exquisite free-kick from Guthrie, who curled the ball over the wall and beyond the flat-footed Scott Carson from 25 yards.
West Brom had the perfect of second-half starts, Dorrans again the provider when he put a cross from the left on the plate for Bednar, whose close-range header was somehow turned on to the bar by Harper, only for the striker to head in the rebound.
United hit back for a second time and were level again after 54 minutes following a howler by Carson.
Jose Enrique whipped in the ball from the left and Lovenkrands headed goalwards, where Carson hopelessly out of position saw the ball hit the post and rebound into the net off him.
Another surging Enrique run saw him tee up Nolan on the edge of the box, but the Magpies top scorer chose to sidefoot the ball which was comfortably held by Carson.
At the other end, Olsson had a great chance with a header nine minutes from time that he placed wide when he should have done better.
That though was nothing to the miss from substitute Miller two minutes later, when he found the goal gaping following a Jerome Thomas cross which he hit against the post when a goal appeared a formality.