After Higuain had hit the post from an offside position the Argentine came close to breaking the deadlock when he swivelled and fired narrowly wide from eight yards as the hosts created the better of the chances in the opening stages, with Udinese's early efforts limited to a long-range strike from Silvan Widmer.
© Getty Images
Karnezis kept his side level with two good pieces of goalkeeping as Napoli continued to knock on the door, first when he dived low to keep out Higuain's effort before he smothered the ball at the feet of Callejon minutes later after Higuain had slipped the Spaniard through.
The prominent Higuain saw his effort drift wide as he found another sight of goal, and with the striker at the heart of all of Napoli's attacking play it was no surprise that it was he who broke the deadlock shortly after half-time.
The 27-year-old was played in by Jorginho and under pressure from a defender he rolled the ball across Karnezis and inside the far post from a tight angle to give his side the lead.
Udinese's best chance of an equaliser came when Jose Reina had to react smartly to turn away Widmer's bullet header, but it was Higuain's contribution that was the telling one as Napoli extend their undefeated run to 15 matches and moved up to third.