Swindon had the first chance of the match in the first minute but an Aaron Brown's quick free-kick was easily pouched by 'keeper Tommy Lee.
Both sides then sparred at each other in the opening exchanges. The first goal came in the 27th minute when defender Jerel Ifil took a wild slash at a Kevin McIntyre corner only to slice the ball to the far-post where Murphy scored with a brave diving header.
Macclesfield might have had another in the 35th minute when a Colin Heath cross was deflected to Martin Bullock at the back-post, his shot went flying inches past the opposite angle.
Swindon had another free-kick on 39 minutes, this time sub Paul Evans warmed the fingers of Lee with a 25-yard drive.
The visitors again went close after the break when a Lee Peacock cross found Brown on the edge of the box, his low skidding shot was palmed wide by Lee.
Macclesfield took the game by the scruff of the neck in the 52nd minute when Danny Swailes met a McIntyre corner with a firm header, the ball rebounded to Murphy who toe-poked it under 'keeper Phil Smith from close range.
Swindon were handed a life-line in the 64th minute when Lee fumbled a Brown corner and Curtis Weston's shot deflected off Peacock into the roof of the empty net. Peacock was then unlucky in the 69th minute as his low drive was blocked on the line by Bullock.
Swindon then went all out for an equaliser and Macclesfield have Swailes to thank for a stunning last ditch tackle on sub Blair Sturrock who was about to pull the trigger from 15-yards.