Peterborough won a five-goal thriller despite the shock resignation of boss Steve Bleasdale just before kick-off. Posh, with club owner Barry Fry taking charge, dominated early on but fell behind when John Miles hammered home.
Danny Crow levelled from an Adam Newton cross and David Farrell put Posh 2-1 up with a header from Lloyd Opara's cross.
Miles drew Macclesfield back to 2-2 from close range before Crow hit a last-gap winner for Posh after being set-up by Tim Ryan.
Peterborough: Tyler, St. Ledger, Bolland (Opara 65), Arber, Ryan, Newton, Carden, Gain, Day (Farrell 61), Logan, Crow.
Subs Not Used: Harrison, Plummer, Fry.
Booked: Ryan.
Goals: Crow 71, Farrell 83, Crow 90.
Macclesfield: Deasy, Brightwell, Morley, Teague, Sandwith, Harsley, McIntyre, Navarro, Bullock (Miles 20), Richardson (Townson 72), McNeil.
Subs Not Used: Briscoe, McDonald, Smart.
Booked: McIntyre.
Goals: Miles 62, 89.
Att: 3,002
Ref: P Crossley (Kent).