Charlton turned in an abject performance at Sixfields on Saturday, as they slumped to a 2-1 defeat.
Addicks old boy, Michael Smith opened the scoring, Jordan Botaka equalised before John-Joe O’Toole fired home the second half winner.
Lewis Page, Patrick Bauer and Frederik Ulvestad came back into the team at the expense of Johnnie Jackson, Jorge Teixeira and Joe Aribo.
The game was a scrappy affair but it was Northampton who took the lead after 32 minutes. Aaron Phillips delivered a terrific cross from the right for Smith to head home.
The lead was short lived, Charlton levelled just two minutes later.
Ezri Konsa’ header from Ricky Holmes’ left-winger was saved, but Botaka stabbed the rebound home.
John-Joe O’Toole netted the winner just past the hour mark. The midfielder latched on to Teixeira’s poor clearance to score what proved to be the winning goal.
The Addicks looked disjointed, and offered very little after they fell behind.
Just six points clear of the drop zone, and with games against three of the top five in their next four matches, Charlton will be looking nervously over their shoulder.
Charlton: Rudd; Byrne, Bauer (Teixeira 46), Konsa, Page (Chicksen 74); Holmes, Crofts, Ulvestad, Botaka; Magennis, Novak (Watt 76).
Subs (not used): Phillips, Jackson, Aribo, Dasilva.
Goal: Botaka 34.
Booked: Watt (90 foul).
Northampton: A.Smith,;Phillips, Zakuani (Diamond 22), Nyatanga, Buchanan; Williams (Anderson 68), O’Toole, Taylor, Wylde; (McCourt 80), M.Smith, Richards.
Subs (not used): Moloney, Anderson, Beautyman, Cornell
Goals: M.Smith 32, O’Toole 62.
Referee: Ben Toner (Lancashire).
Attn: 7,118 (1,424 Charlton).
TAGS: Charlton Athletic