Macclesfield goalkeeper Jonny Brain gifted Bradford victory at Moss Rose with a moment of madness.
Brain made a hash of a long clerance from Kyle Nix 15 minutes from time to present 18-year-old David Brown with a simple goal on his debut.
Bradford keeper Scott Loach then denied Macclesfield an equaliser when he saved Terry Dunfield's penalty after Danny Thomas was brought down by Joe Colbeck.
Macclesfield threw men forward at the death but Bradford's defence held firm.
Macclesfield: Brain, Izak Reid, Cresswell, Hessey, Ashton, Levi Reid (Green 69), Dunfield, Ashmore (Tolley 62), Thomas (Blackman 85), Symes, Gritton.
Subs Not Used: Lee, Dimech.
Bradford: Loach, Starosta, Wetherall, Clarke, Heckingbottom, Colbeck, Penford (Evans 87), Bullock, Nix, Topp (Brown 69), Thorne (Conlon 76).
Subs Not Used: Ricketts, Moncur.
Goals: Brown 75.
Ref: F Graham (Stanford-le-Hope).