The Addicks' watching managerial team of Alan Curbishley and Mervyn Day could not have witnessed a better start at Dagenham & Redbridge's Glyn Hopkin Stadium.
For after just 90 seconds, the ex-Hammers duo saw former Upton Park trialist Stephen Hughes cross for Sam to chest home from six yards as referee Singh turned away the host's vain appeals for an offside flag.
And midway through the half, Charlton would have doubled their lead but for Tommy Laws' timely slide on Karl Beckford as he burst into the box.
With the richly-experienced Richard Rufus and Spurs' on-loan Chris Perry at the heart of a five-man Addicks defence, Hammers' neat approach play sadly counted for nothing.
Indeed, when Mark Noble did finally skip through on the half hour mark, Perry crudely thwarted him at the expense of a booking, and shortly afterwards the lively, albeit luckless, young Hammer sliced his 20-yarder over the right-hand angle.
Right on half-time, Rufus showed his mean streak too with a crude lunge on Richard Garcia that saw him join Perry in the book.
And as the tempo finally rose, Mark Noble - in the thick of things again - followed for an equally feisty lunge on Nathan Ashton.
Early in the second half, Chris Cohen whipped over an unplayable centre that only needed a touch and, as the hour mark approached, referee Singh did little to endear himself to Hammers when he refused to point to the spot after Garcia's steamrollering stroll to the edge of the six yard box was foiled by Osei Sankofa's trip.
Just as Hammers started to look threatening, Sam dealt them a killer blow midway through the half when he ghosted into the box and slotted his low 12-yard effort wide of Stephen Bywater.
Seconds later, the Addicks' goal-getter almost claimed the matchball, but this time his low shot lacked pace and Bywater comfortably saved.
At the other end, Sofiane's scorching 20-yarder crashed back off Sergio Leite's right-hand post and across the face of goal, while David Noble then fired just inches wide from similar range.
And when Garcia blasted his angled shot across goal with just 10 minutes remaining, it merely underlined the fact that this was never going to be West Ham's night.
Team: Bywater, McClenahan, Cohen, Laws, Lumsden (Pearson 66), Kilgallon, M Noble, D Noble, McMahon (Blewitt 81), Sofiane, Garcia. Subs unused: Reed, Tattum, Wright, Bunce.