And it was Teddy Sheringham who supplied the three points with a close range goal after Luke Chadwick supplied the cross.
Reading could have taken the lead early on when Hughes blazed over in the first minute when he was unmarked in the box, while West Ham countered with Marlon Harewood, who was foiled by a defender before Sergei Rebrov swung in a cross for Teddy Sheringham to head just wide.
Kitson and Forster then forced good saves from Steve Bywater before Harewood poked just wide and Mullins headed over a Mattie Etherington corner.
Sidwell's header was saved one-handed by Steve Bywater before Forster drilled a shot wide on the immaculate Upton Park turf.
Reading then suffered a blow when Glen Little, one of their best players on the night, had to go off; he was replaced by new signing from America, Bobby Convey.
Just before half time, Marlon Harewood was unlucky to be foiled by Hahnemann after Sheringham put him through.
Just after the break, Sheringham hit a stinging drive just wide of the top corner after making a corkscrew turn.
With the game turning into a real end to end affair, Kitson headed just wide at the far post while Harewood tested Hahnemann before just overhitting a pass that would almost certainly have set Rebrov up to score had Hahnemann not got there first.
A quarter of an hour into the second half Alan Pardew brought Anton Ferdinand on for Andy Melville, switching Tomas Repka across to centre half.
Christian Dailly can consider himself unlucky to have been booked for an innocuous challenge on Forster in the centre circle.
Bobby Zamora became the second West Ham substitute when he came on for Harewood - as he did on Saturday.
That switch was shortly followed by Luke Chadwick coming on for Sergei Rebrov on the right.
Luke's impact was immediate; a clever turn past two players and low cross left Sheringham with the relatively easy task of turning home from close range.
Cheers turned to jeers when Bobby Zamora was booked after shooting when the whistle had gone for him being offside.
Chadwick showed he could defend as well as attack with a couple of well-timed challenges against the team he once played for on loan.
Adam Nowland was on the bench instead of Jobi McAnuff while Luke Chadwick filled the sub's place vacated by Chris Cohen, who replaced the suspended Rufus Brevett.
Sergei Rebrov and Teddy Sheringham both made their home debuts, with Luke Chadwick making his full debut as Michael Carrick watched from the stand.