Federico Bernardeschi scored a free kick on his return to Fiorentina, before Higuain killed them off with a late finish to provisionally move Juve top of Serie A.
Fiorentina were initially awarded a penalty in the 18th minute of the match following a Giorgio Chiellini handball, but the decision was overturned in incredible circumstances as the referee first threatened to use VAR before seemingly deciding against the award of the spot kick following a chat with his assistant.
Italian frontman Bernardeschi whipped in a low free-kick strike beyond the outstretched arms of Marco Sportiello, before the Argentinian striker sealed victory in the closing stages at the Artemio Franchi Stadium.
The 23-year-old curled in a free-kick after 56 minutes for his fourth goal in six Serie A games started for Juventus to break the deadlock.
Juve - who have kept 15 clean sheets in their last 16 games - have gone two points above Napoli, who host Lazio in their game in hand on Saturday (19:45 GMT).
The visitors, however, struggled throughout the first half, failing to create any danger on one end while fending off attacking forays by Fiorentina down both wings.
Fiorentina continued to threaten a goal of their own, with Buffon called into action 70 minutes in, charging off his line to deny the home side with his feet.
With four goals in six league starts so far this season, the Italian global is doing his best to make it hard for Juventus head coach Massimiliano Allegri to leave him out of the playing XI.
"I was waiting for the referee's decision ..." "[Spurs] have excellent technique, but Champions League games are tight".
"But I made a career choice and now I play for another team".