The midfielder fired in the winner shortly before the hour with low drive from the edge that flew past Dagenham keeper Chris Lewington and in off the visitors' right-hand post.
That meant a successful debut for Charlton striker Paul Benson who switched to the Valley from Daggers just 24 hours previously.
he forward was unable to mark the occasion with his first goal for his new club but Phil Parkinson ran out deserved winners after surviving early pressure from the visitors.
Charlton keeper Ross Worner almost handed John Still's side the chance to draw level late on but recovered after spilling a routine cross.
The tension on the pitch spilled over into the dug-outs with Addicks assistant boss Tim Breacker sent to the stands shortly before Racon struck the winner.