Buffon was at fault moments later, however, as he spilt the ball at the feet of Marek Hamsik, who tucked it home only for his celebrations to be cut short by the linesman's flag.
Hamsik threatened again in the 10th minute as he latched on to a cross before curling an effort goalwards, but once again Buffon was there to keep the scores level.
Juventus' first sight of goal came in the 26th minute as Pablo Osvaldo showed good strength to hold onto the ball inside the box before teeing up Stephan Lichtsteiner, whose strike was saved by Pepe Reina.
Napoli came close again three minutes later as Faouzi Ghoulam led a break away before cutting the ball back across the box for Callejon, who was again denied by Buffon.
The hosts did finally take the lead with eight minutes to go until the break when Ghoulam again combined with Callejon, but this time the Spaniard was able to find a way past Buffon from close range.
Juventus tried to respond before the break as Osvaldo threatened with an acrobatic effort, but he steered his strike wide as the league leaders went into half time behind.