First-half goals secured a maiden away victory of the season for the Hammers, while another defeat adds pressure to Mark Hughes with the Rs rooted to the bottom of the table
Jarvis opened the scoring in the third minute with a header at the back post before Vaz Te doubled the visitors' lead before the interval with a neat finish from a narrow angle.
Adel Taarabt provided a lifeline for the hosts with a stunning curled effort after the break but QPR lacked the cutting edge to be able to break West Ham’s sturdy defence for a second time, particularly after Samba Diakite was sent off 16 minutes after coming on as a second-half substitute.
Questions of QPR’s inconsistency at the back were asked after just three minutes of play and West Ham took full advantage of poor marking from the hosts as Vaz Te’s neat one-two with Kevin Nolan led to the latter’s chipped shot which Jarvis was able to meet at the back post and nod beyond Julio Cesar.
Hughes’ men struggled to settle on the ball and with the industrious trio of Nolan, Mohamed Diame and Mark Noble in the middle, QPR’s 4-4-2 system left Esteban Granero and Alejandro Faurlin constantly exposed and outnumbered.
QPR’s brightest outlet was Shaun Wright-Phillips on the right flank and the winger was able to cut inside on a few occasions to provide half-chances, the best of which fell to Granero but the Spaniard blazed his first-time effort over from just inside West Ham’s area.
The fragility of Hughes’ defence was exposed for the second time of the evening in the 35th minute as Noble’s corner led to a scramble in the hosts’ box. The ball was scuffed clear into the path of James Tomkins on West Ham’s right and his cross to the back post was turned in neatly by Vaz Te.
After the half-time whistle was greeted with a chorus of jeers from the home support, QPR begun the second half in a similar fashion to their lifeless display before the break and Hughes waited just six minutes to bring off Ji-Sung Park, who was ineffective on the left flank, and Wright-Phillips, who had faded, for Diakite and Taarabt.
The Moroccan had an instant impact and provided QPR with their lifeline as his curled effort from outside of the box, after cutting side from the left flank, left Jussi Jaaskelainen rooted to the spot.
QPR began to find their rhythm and after a neat exchange on the edge of West Ham’s area, Granero hit a thumping shot which forced Jaaskelainenn to parry away. Allardyce’s men responded and could have put their three points beyond doubt but Vaz Te’s strike, which was bound for the top corner, was expertly tipped onto the bar by Julio Cesar.
But any revival from the hosts was quashed by Diakite’s late challenge on Guy Demel which resulted in the midfielder’s dismissal and leaves QPR without a victory this season and Hughes under increasing pressure.