Seol Ki-Hyeon's second-minute winner may have been the visitors' only shot of the game, but it was still enough to send Steve Coppell's men onwards and upwards, while consigning wobbling West Ham - who have not won since the opening day of the season - to a fifth straight defeat.
The Hammers had made four changes following Thursday evening's UEFA Cup exit in Palermo as Christian Dailly, Hayden Mullins, Matthew Etherington and Yossi Benayoun returned in place of James Collins, Javier Mascherano, Lee Bowyer and Marlon Harewood.
Reading on the other hand, were forced into just one switch following their confidence-boosting draw with Manchester United, last weekend as Ulises De La Cruz came in for Graeme Murty.
And after seeing their Euro dreams turn into nightmares in Sicily, the Hammers were soon struggling on the rain-sodden home soil of Upton Park, too.
Indeed, there was only a minute on the clock when Bobby Convey rolled a quick free-kick to Seol, who let fly with a rising 25-yarder that flew beyond the sprawling Roy Carroll and under the right-hand angle.
Already staring that fifth successive defeat in the face, West Ham quickly set about repairing that early damage as Carlos Tevez forced Marcus Hahnemann to save his low 18-yarder, as it skidded through Upton Park puddles.
Shortly afterwards, Reading's American keeper had his palms scorched by compatriot, Jonathan Spector, who let fly from 20 yards and then the marauding Nigel Reo-Coker unselfishly opted to pass to Carlton Cole when he really should have pulled the trigger himself.
With Tevez generating the Hammers' spark, an East End equaliser still looked feasible but, unfortunately for the Argentinian, his team-mates were not firing on all cylinders in the damp conditions and Pardew's side headed back down the tunnel at the break still trailing.
Early in the second half, Dailly's glancing header forced Hahnemann into an extended save before a couple of wayward Tevez efforts forced the Royals' fans to take cover behind the Reading goal.
With the clocking now ticking down, West Ham still had nothing to show for their all their possession and approach play and that was the cue for the Hammers' boss to replace his strikeforce for the final 20 minutes.
But with Upton Park still coming to terms with the curious withdrawal of Tevez, the switch almost paid dividends when the newly-arrived Teddy Sheringham sent a perfectly-weighted reverse pass out to Etherington, whose low cross into the six-yard box just eluded substitute Bobby Zamora.
And by the time stoppage time arrived, West Ham simply knew that it was not going to be their day when Benayoun saw the industrious Steve Sidwell somehow head his clever chip out from underneath the bar, to leave Reading with all three points and West Ham without a goal in 488 minutes of play