Napoli beat 10-man Lazio 2-1 to close the gap on leaders Juventus to six points and consolidate second place in Serie A.
Napoli have 47 points from 20 games and are now seven ahead of third-placed Inter Milan who were held to a goalless draw at home by Sassuolo on Saturday.
But it was a damaging defeat for Lazio who drop out of the Champions League places into fifth at the expense of city rivals Roma.
Eusebio Di Francesco's Roma are one point ahead of Lazio who host seven-time reigning champions Juventus next weekend.
Napoli were without suspended defender Kalidou Koulibaly, captain Marek Hamsik and forward Lorenzo Insigne.
But Carlo Ancelotti's side could have won by a larger margin with Milik and Fabian Ruiz both hitting the woodwork early.
Spanish forward Callejon scored his first Serie A goal this season after 34 minutes with forward Milik's superb free-kick three minutes later giving the Pole his seventh goal in eight games.
Ciro Immobile pulled one back for Lazio after 65 minutes at the San Paolo stadium, but the visitors were struggling as they played the last 20 minutes a man down after Francesco Acerbi was sent off for a second yellow card.
"We were missing a lot of players, but you really couldn't tell at all, which shows our strength in depth," said Ancelotti.
"We had moments of difficulty, some of which we could have dealt with better and there were some naive errors, but overall there was a lot of quality."
Earlier Colombian forward Duvan Zapata scored four goals as ambitious northerners Atalanta thrashed struggling Frosinone 5-0 to bring his tally to 13 in the last seven league games.
The side from Bergamo are just two points off the final Champions League berth. In Florence, Sampdoria held 10-man Fiorentina 3-3 in a game between Europa League hopefuls.
Colombian forward Luis Muriel bagged a brace on his first appearance for Fiorentina since his loan move from Sevilla, with Fabio Quagliarella getting a double to join Cristiano Ronaldo on top of the goal scoring charts with 14 this season.
The side from Genoa are eighth -- one point off the Europa League berths, with Fiorentina three points behind in tenth.
Juventus -- fresh from winning a record eighth Italian Super Cup trophy in midweek against AC Milan thanks to Ronaldo's goal in Saudi Arabia -- take on lowly Chievo on Monday as Gennaro Gattuso's AC Milan travel to Genoa.
(This story has not been edited by Business Standard staff and is auto-generated from a syndicated feed.)