Kagisho Dikgacoi's second-half strike settled the south London derby as Crystal Palace beat Charlton in the league at The Valley for the first time since 1968.
The South African midfielder lashed home a superb finish as rejuvenated Palace made it back-to-back wins with the 1-0 triumph - having previously lost their opening three matches.
They also leapfrogged their newly-promoted neighbours, who have now lost two on the bounce, in the npower Championship table.
Palace could have been two up in the opening 10 minutes with teenage winger Wilfried Zaha tormenting Charlton's defence early on.
Charlton will feel hard done by, though, not least because Bradley Wright-Phillips had what looked a perfectly good goal ruled out for offside.
The striker, watched by father and Palace legend Ian Wright in the stands, appeared to be onside as he buried a header past Julian Speroni, but the linesman's flag cut his celebrations short.
The hosts were well on top as the first half came to a close with Yann Kermorgant heading Johnnie Jackson's cross wide and Dale Stephens, who saw a deadline-day move to Aston Villa fall through, driving narrowly over.
But it was Palace who took the lead five minutes after the interval when Charlton failed to deal with Garvan's corner. Damien Delaney was unmarked as he headed the ball back to Dikgacoi, and the former Fulham midfielder also had the freedom of the Charlton penalty area as he crashed the ball past Hamer from 12 yards.
The hosts had chances following Dikgacoi's decisive strike just after half-time, but Palace held on to take the points the short journey back to Selhurst Park.