Ricky Holmes netted the winner as Charlton secured south London derby bragging rights with a 1-0 win over AFC Wimbledon.The winger found the top corner from a free-kick in the 78th minute to keep the Addicks fourth in Sky Bet League One. Chances were at a premium in a lacklustre opening period, with Jake Forster-Caskey blazing an early free-kick over for the hosts and the Dons' Lyle Taylor firing wide when well placed.Tariqe Fosu saw a very half-hearted penalty appeal rightly ignored by referee Ben Toner in the 24th minute after going to ground in the box very dramatically.Fosu's strike was charged down by a Wimbledon defender midway through the second half after being picked out by Jay Dasilva's delivery.Dons substitute Callum Kennedy's 74th-minute free-kick was deflected behind moments before Deji Oshilaja blazed over for the visitors.But it was Charlton who finally broke the deadlock four minutes later when Holmes won a free-kick inches outside the area on the left.He stepped up to take the set-piece, drilling his effort into the top corner beyond the reach of Wimbledon goalkeeper George Long.The Dons were denied what would have been a bizarre leveller when Chris Solly headed an attempted clearance on to his own bar.But Holmes' moment of magic proved decisive as the Addicks maintained their promotion push.