The visitors dominated the opening half hour but came up against a brick wall in Manchester United on loan keeper Tommy Lee.
In the 16th minute he brilliantly tipped wide a Kelvin Langmead drive, then in the 31st minute he flung himself full length to claw out a Neil Sorvel bullet.
Macclesfield capitalised two minutes later when former white van man Matthew McNeil, who was plucked from the conference north three weeks ago, curled his right boot round a Kevin McIntyre cross to tuck home at the far post.
The Cheshire side might have extended his lead moments before the break but having danced through the heart of the defence, midfield man Danny Whitaker throw straight at Joe Hart from 15 yards.
Whitaker again picked out Hart seconds after the interval with a looping volley which the keeper saved at the second attempt. Former Premiership player Martin Bullock sealed a vital three points in the 61st minute with an audacious 25-yard kick that left Hart flapping at thin air.
Macclesfield might have added another late on but with only the keeper to beat, Whitaker blazed a volley over the bar.