West Ham United showed impressive resolve to earn their second win in four days and inflict West Bromwich Albion's fourth straight defeat.
The hosts burst out of the blocks at The Hawthorns and took a deserved lead thanks to Craig Dawson's powerful 10th minute header.
But West Ham hit back with captain Kevin Nolan - drafted in to replace Mark Noble who has a calf problem - nodding in the equaliser after 35 minutes for his first goal of the season before defender James Tomkins won it on the stroke of half-time.
Struggling West Brom ramped up the pressure in the second half, with Victor Anichebe causing several problems, but they failed to find the breakthrough.
West Ham remain fifth - one point below Manchester United - after their fifth win in eight matches.
Buoyed by his side's impressive, albeit fruitless, display against Arsenal on Saturday, West Brom head coach Alan Irvine included Saido Berahino and Anichebe from the start in an attacking line-up, while Chris Baird replaced the injured Sebastien Pocognoli at left-back.
Baird's free-kick fell invitingly for Nigeria striker Anichebe in the seventh minute, but his effort was deflected over, before a succession of set-pieces and West Brom pressure led to Dawson's opener.
Graham Dorrans' well-placed free-kick was met powerfully by the head of the defender, with West Ham goalkeeper Adrian, who came off his line, well beaten.
Dorrans then fired over before a strike from ex-Baggies midfielder Morgan Amalfitano, which was excellently blocked by Joleon Lescott, shook the visitors into action.
Nolan's bicycle-kick was well saved by Ben Foster before West Ham levelled 10 minutes from the interval, as the rebound from Andy Carroll's fierce overhead effort - which was also kept out by the West Brom goalkeeper - was headed in from close range by the skipper.
Sam Allardyce's men turned the screw and Cheikhou Kouyate had a curling effort turned behind by Foster, while Chris Brunt hobbled off for the hosts to be replaced by Youssouf Mulumbu.
And West Ham capped off their first-half turnaround when, in the third minute of stoppage time, Tomkins climbed above Dawson at the back post to nod Stewart Downing's corner across the face of goal and in. It was his first goal since he scored at Wigan Athletic in October 2012.
Dawson had a glorious chance to double his tally eight minutes into the second half when Lescott's header was completely missed by Berahino, but the defender, who took a touch, could only shoot just wide from 12 yards.
Two half-chances for Berahino kept the home fans interested, and West Ham were beginning to feel the pressure when Adrian did well to keep out a powerful left-footed strike from Anichebe on the turn.
Anichebe was a constant threat and headed at Adrian in the 74th minute, while Irvine showed his intent by bringing on forwards Silvestre Varela and Brown Ideye.
Adrian then produced a magnificent save with his legs to keep out Anichebe, and Dorrans acrobatically shot wide as West Ham defended desperately - which was ultimately enough for victory.
West Brom head coach Alan Irvine: "It's bitterly disappointing as we started the game pretty well and got ahead.
"We made a couple of mistakes and people started getting nervous. When the equaliser came, I felt we could deal with that at half time.
"But, the second goal then made our job even harder.
"I thought the second half was very, very good and we deserved to get something out of that game."
West Ham manager Sam Allardyce: "It was a tremendous recovery after we went 1-0 down. It was a great, great away win for us.
"If we can have a good Christmas, then we'll have a look at what we can achieve over the second half of the season. I'm hoping we'll get Mark Noble and Alex Song back from injury for the weekend, and that wil give me the selection headache I want."
|06 Dec 2014||v Hull (A)|
|20 Dec 2014||v QPR (A)|
|13 Dec 2014||v Aston Villa (H)|
|26 Dec 2014||v Man City (H)|
|28 Dec 2014||v Stoke (A)|
|01 Jan 2015||v West Ham (A)|