Two sloppy goals condemned Hammers to a disappointing 2-0 loss at Reading, as Alan Pardew's return to his previous club ended on a sour note.
Striker Dave Kitson struck either side of half-time following lapses in concentration from Andy Melville to make it three straight defeats away from home for Hammers, who are now looking cautiously over their shoulder as the play-off race hots up.
The result rounded off a miserable afternoon for Pardew, who coped admirably with the jeering and booing from his former supporters but was left frustrated and angry by the display from his own team.
Hammers had been handed a boost prior to kick-off by the return to fitness of Hayden Mullins and Don Hutchison, although both had to settle for a place on the subs bench as Pardew named an unchanged starting line-up following last week's 2-1 victory against Gillingham.
In a lively and competitive opening, the visitors almost took the lead in the 11th minute. After Michael Carrick had been fouled just outside the penalty area, a cleverly-worked free-kick saw Marlon Harewood spin on the ball and send in a fierce, bending effort that Reading keeper Jamie Ashdown superbly tipped round the post.
Despite the fact that Harewood's strike would turn out to be Hammers' only real effort on target in the entire 90 minutes, Pardew's men enjoyed a fair amount of possession in a relatively even first half and appeared to have the attacking edge over their opponents when it came to creating chances.
David Connolly went close in the 28th minute when he beat the offside trap and latched on to Zamora's deft cross, but his clipped effort bounced just inches past the post, while a couple of typical mazy runs from Matt Etherington almost led to greater things.
However, with the hosts gradually starting to stamp more authority on the game, the Hammers boss then made a change that surprised many among the 4,600 travelling crowd. Having seen veteran winger John Salako allowed a little too much time and space out on the left, Pards sent on Adam Nowland in place of Harewood in the 29th minute and pushed the more defence-minded Nigel Reo-Coker out wide to combat the danger of his former Crystal Palace team-mate.
Harewood's displeasure at his substitution was obvious for all to see and, although the tactical switch certainly helped to quell the threat from the left flank, it all went wrong for Hammers six minutes later when Reading opened the scoring with a goal provided from the right.
Murty's searching pass forward was dummied by Dean Morgan and, with Melville caught out by the move, former Cambridge striker Kitson ghosted in behind the Welsh international defender to slip the ball past Bywater from six yards out.
Things went from bad to worse just eight minutes into the second half. Having been penalised for a shove on an opponent near the touchline, Tomas Repka was then booked for another push off the ball on midfielder Steven Sidwell - his 15th yellow card of the season that means a three-match ban at a vital stage of the season.
However, things then got worse as, from the resulting free-kick, the ball found it's way to the far post where, having lost his marker Meville again, Kitson lashed home a left-foot volley from close range.
Pardew then replaced Connolly with Brian Deane in the hope of adding a greater presence to the front-line but, with the First Division's top goalscorer now off the pitch, the outlook didn't look bright for Hammers.
Reading did well to protect their lead and keep possession as the visitors pushed men forward in search of a comeback, but a cutting edge was sadly lacking as Hammers simply ran out of ideas in the closing stages.
The best they could offer was a Deane volley that flashed wide and a Zamora header that looped the wrong side of the post, while Don Hutchison's late appearance failed to add any further attacking impetus.
Hammers must now bounce back again from a disappointing performance and result on their travels and, with two vital games in two days next weekend, the chances of securing that all-important top six place will rest heavily on how we fare against Derby County and Crystal Palace during the Easter period.