Controversy surrounded Albion's ultimate winner, with Rob Green claiming Marc-Antoine Fortune had backed into him as he reached for the ball. Djibril Cisse had pulled one back after Chris Brunt opened the scoring in the first half.
Green continued in goal for Rangers, after Julio Cesar was not deemed fit enough to return. A well publicised disagreement between Harry Redknapp and Jose Bosingwa during the week prompted the manager to fill the right back role with youngster Fabio da Silva.
Youssouf Mulumbu came straight back in after his suspension in the place of Graham Dorrans, while Marc-Antoine Fortune replaced Peter Odemwingie on the wing, both players dropping to the bench. Romelu Lukaku started ahead of Shane Long once again.
Stephane M'Bia went close with a long rage shot early on, but Albion started the match the brighter, Mulumbu seeing a lot of the ball in the middle. Boxing day sales in the area and lengthy traffic forced officials to delay the kick off by 15 minutes.
The much talked about Adel Taarabt, who had found out before the game he wouldn't be representing Morocco in the Africa Cup of Nations, tested Foster from distance and the goalkeeper did well to get down and concede the corner.
The Baggies weren't able to create too much in the way of a chance, but they looked tidy as the Hoops' defence held firm. Mulumbu did well to lay the ball off to Zoltan Gera, who rushed his shot and fired his first time effort well wide.
Up the other end, Shaun Wright-Phillips caused havoc down the left, sneaking past Billy Jones and crossing for Jamie Mackie, who should maybe have done better with his header.
Albion made their early dominance count by taking the lead in the 29th minute. Fortune cut inside from the right and laid the ball off to Chris Brunt. The captain unleashed a fierce, low drive from 25 yards beyond Green, his first of the season.
QPR replied immediately with another M'Bia strike, which Foster dealt with again. Mackie then robbed Popov on the far side, but McAuley's header behind spared the Macedonian's blushes. Popov had been claiming a foul and had to be substituted for Liam Ridgewell.
Taarabt whistled a free kick just wide of the post with Foster rooted, while Clint Hill headed a corner just wide after Mackie's persistence had earned the set piece initially.
Albion ended the half slightly more on top, as Morrison (with help from Lukaku) shrugged off a number of challenges but his shot just beat Green's post.
Whatever Redknapp had said at half time had taken effect, as pressure ensued on the visitors' box, Taarabt's free kick headed wide of goal by the dangerous M'Bia.
This pressure faded, and Albion took advantage, but questions will be asked about the legality of the goal. Continuous pressure involving Mulumbu and Jones resulted in a corner, and Brunt's kick was headed towards goal by Olsson. Green then proceeded to carry the ball into the net under pressure from Fortune. Comparisons were immediately made between this incident and that involving Victor Anichebe and Jussi Jaaskelainen when Everton met West Ham on Saturday, which resulted in a free kick to the goalkeeper.
This dented the Hoops' rhythm, and Albion threatened to score further goals. Fantastic football was played in the middle between midfielders Mulumbu and Morrison before Green thwarted Lukaku. Morrison's cross across the box a few seconds later was dangerous, but Lukaku couldn't reach it.
Green was on hand to prevent Belgian loanee Lukaku on the break following a splendid ball from Brunt, but Rangers were allowed back in on 68. A quick free kick allowed sub Samba Diakite to run at the defence, before the midfielder slipped the ball through to Cisse, who chipped over the onrushing Foster.
Rather than constant pressure from the hosts, the game opened up and the play was instantly more exciting. Green claimed the ball before the hard working Lukaku could get a shot in, while Fortune finished brilliantly only to see the offside flag go up.
The home side had a big shout against Liam Ridgewell for handball in the penalty area, which was waved away by Chris Foy, although on second glance there was substance to the appeal.
Foster produced a wonder save to deny Hill's header late on, and Albion rode out the consummate pressure and series of corners to claim back to back victories.
Match ratings: QPR- Green 6, Fabio 6 (Hoilett 5), Hill 7, Ferdinand 6, Traore 6, Faurlin 6 (Diakite 5), M'Bia 6, Wright-Phillips 6, Mackie 6, Taarabt 7, Cisse 6
WBA- Foster 7, Jones 7, McAuley 7, Olsson 7, Popov 5 (Ridgewell 5), Mulumbu 7, Morrison (Tamas 85) 8, Brunt 6, Gera 6, Fortune 7, Lukaku 6 (Long 5)