West Brom piled more pressure on QPR boss Mark Hughes with a 3-2 win that left the Londoners bottom of the Premier League and allowed the winners to celebrate their best home start to a top-flight season in almost a century.
West Brom are now fourth in the table, five points behind leaders Chelsea, while this defeat was Queens Park Rangers' fifth in seven matches, leaving them on just two points.
James Morrison opened the scoring for the hosts in the fifth minute and midfielder Zoltan Gera made it 2-0 in the 22nd.
Adel Taarabt pulled one back for QPR in the 35th but Youssouf Mulumbu scored for the Baggies with five minutes remaining, before Esteban Granero added a consolation in the second minute of injury time.
Hughes was able to bring defenders Jose Bosingwa and Anton Ferdinand back into the line-up after injury, while Taarabt made his first start since the opening match of the season.
Ferdinand, the man caught up in the John Terry racism row, was booed by some Albion fans.
QPR were being pulled apart in the first half-hour and it was no surprise when Morrison got the better of Ferdinand to head in a Shane Long cross.
And it was Ferdinand's slip that gifted an attempted clearance straight to Gera, who scored from 10 yards out.
Taarabt reminded the crowd of his technique and skill with a smart goal that gave QPR a lifeline.
On the edge of the penalty box, the Morocco midfielder brought the ball under control and volleyed it beyond goalkeeper Ben Foster.
Rangers captain Park Ji-Sung was cautioned at the end of the first half for a lunge at Gera.
The west London side emerged for the second half with much more purpose, forcing Albion boss Steve Clarke into replacing both his strikers to maintain their attacking threat.
Despite QPR threatening to equalise, the Black Country side sealed their victory when Mulumbu made it 3-1 following a quick exchange of passes, meaning Granero's injury time strike counted for little more than a consolation goal.
West Brom's fourth win on their ground is the Black Country side's best start to a top flight season at home since 1919.