Charlton ignited their promotion bid by roaring into second following a 5-1 drubbing of Peterborough.
The Posh horror show began after 15 minutes when skipper Grant McCann was caught dithering in the box by Scott Wagstaff.
McCann escaped with a yellow card for hauling down the Addicks man but there was no further let-off as Johnnie Jackson scored from the spot.
Charlton only had to wait 10 minutes for a second as Therry Racon blasted home from 12 yards and Jackson completed a lightning counter-attack in the 36th minute after a Paul Benson shot had deflected into his path off defender Kelvin Langmead.
More Martin magic sealed the points soon after as he cut inside from the left flank and beat shell-shocked Posh keeper Joe Lewis with a fine finish.
A triple-substitution at the break did put some fire into Posh bellies and McCann claimed a consolation with a 25-yard free-kick nine minutes into the second period. But their defensive nightmare struck again as on-loan Lewin Nyatanga's under-hit backpass allowed Benson to feed Martin for a simple fifth.