The last time West Brom won four consecutive home games, in 1919, they went on to win the league.
Albion saw off a battling QPR side, but they made it harder than it should have been.
The hosts were fancied going into the encounter, given the visitor's poor form, and early on it looked like it might head that way.
The Baggies welcomed back Peter Odemwingie from his ban, while Jonas Olsson took the captaincy after signing a new contract last night. Gabriel Tamas deputised at right back with Billy Jones and Steven Reid injured.
Mark Hughes gave a start to Adel Taarabt after his goal against West Ham, while Anton Ferdinand and Jose Bosingwa both passed fitness tests.
The home side took the lead within 6 minutes. Excellent work from Shane Long on the right wing resulted in the Irishman picking out James Morrison in the area. The Scot headed home from close range.
This settled the Baggies down, but the away side sparked into life and offered threats from free kicks around the penalty area. One of these set pieces ended in a swift counter attack involving Morrison and Long. The former looked to return the favour to the latter, but Long fired over the cross.
Albion doubled their lead on 22. Morrison was found on the right again, Clint Hill struggling to deal with the movement of the Baggies' midfielders. Anton Ferdinand beat Long to the ball, but his clearance was weak and fell to Gera on the edge of the area. The Hungarian put away his second of the season and it seemed as though normal service was being resumed at the Hawthorns after defeat to Liverpool in the Capital One cup.
West Brom continued to look the better side, but always had to be on alert whenever Taarabt was in possession. The Moroccan was causing problems for out-of-position Tamas and curled an effort over the bar when given too much time.
The winger did reduce his side's arrears before half time. Receiving the ball from the impressive Granero, Taarabt chested the ball before lashing a unstoppable volley past Foster- the first goal scored by the away side at the Hawthorns in the league this season.
Albion had chances through Mulumbu and Gera before the half time whistle, but it remained 2-1.
HT - 2-1
Both sides made one change apiece for the second half, Jara Reyes replacing Tamas at right back, Traore coming on for Hill at left back for QPR.
The away side started much the better side, Albion slack in possession and giving the ball carelessly more than once. The first half chance came to the hosts, as Jara's clever ball in eluded Long.
But Rangers continued to press, the man mountain M'Bia failing to reach a corner while Hughes introduced Junior Hoilett and Jamie Mackie to force the issue further.
Steve Clarke made changes of his own, sending on Lukaku and Rosenberg to see the game out.
QPR's midfield was a big test for duo Mulumbu and Yacob, Granero, Park and Taarabt all looking very smart.
Albion looked to have closed the game out when their two goal advantage was restored with five minutes to go. A clever one-two with Morrison saw Jara pull the ball back on the byline for Mulumbu to notch his first of the season.
But QPR wouldn't lie down. A fantastic performance from Granero was capped off when he scored with a lovely curling effort in injury time. Bosingwa nearly grabbed a late, and perhaps deserved, equaliser with the last kick, but the R's remain without a win, while West Brom move up to fourth.
WBA- Foster 6, Tamas 5 (Jara 5), McAuley 7, Olsson 7, Popov 6, Mulumbu 8, Yacob 7, Gera 6, Odemwingie 6, Morrison 7, Long 7 (Lukaku 5) (Rosenberg 5)
QPR- Cesar 5, Hill 5 (Traore 6), Ferdinand 5, Nelsen 6, Bosingwa 6, Granero 8, Park 7, M'Bia 6, Taarabt 7, Zamora 5, Wright-Phillips 6 (Mackie 5) (Hoilett 5)