Suspected racist chanting halted play at the Stadio Olimpico on Wednesday as hosts Lazio suffered a 2-0 defeat that kept visitors' Napoli's sterling Serie A season on track.
But the main talking point was a three-minute suspension in the second half on the orders of match officials for racist and insulting chanting aimed at Napoli defender Kalidou Coulibaly.
Higuain is bidding to beat Gunnar Nordahl's all-time Serie A record of 35 goals in a single, 20-team season (1950) and after spurning an early chance was soon into his stride, thanks to a slice of fortune.
The Argentine ran on to Callejon's through ball on 24 minutes only to see Federico Marchetti come out to block, but as the ball bounced up Higuain chested it home.
Callejon, who hit a brace in a 5-1 thumping of Empoli last weekend, doubled Napoli's lead three minutes later.