Udinese left the Stadio Maradona empty-handed as Napoli and a rampant Khvicha Kvaratskhelia proved too much to handle.
Former Udinese man Piotr Zielinski opened the scoring from the spot following a tussle between Kvaratskhelia and Festy Ebosele.
The home side pushed forward and doubled their lead when Victor Osimhen slotted home after being released by Matteo Politano.
Udinese tried to fight back and had a chance before the break but Sandi Lovric lifted his shot over the bar at the end of a well-worked training-ground move.
In the second half Kvaratskhelia seemed set on finding the net himself and having struck both posts with two previous chances finally got his goal after cleverly dinking the ball over Marco Silvestri.
Lazar Samardzic offered Udinese a glimmer of hope with ten minutes remaining when he scored a brilliant goal, jinking past the home defence before finishing from close range.
However, a minute later Giovanni Simeone buried any lingering doubts with a header from Kvaratskhelia's cross.
Udinese know they were well beaten by the champions and now all thoughts must turn to Genoa on Sunday.
NAPOLI 4-1 UDINESE (HT 2-0)
Scorers: Zielinski 19 (pen), Osimhen 39, Kvaratskhelia 74, Samardzic 81, Simeone 82.
Napoli (4-3-3): Meret; Di Lorenzo, Ostigard, Natan, Mario Rui; Anguissa (Elmas 83), Lobotka, Zielinski (Cajuste 71); Politano (Lindstrom 63), Osimhen (Simeone 63), Kvaratskhelia (Raspadori 83).
Subs not used: Contini, Idasiak, Demme, Olivera, Zerbin, D’Avino, Zanoli, Gaetano.
Coach: Garcia.
Udinese (3-5-2): Silvestri; Perez, Bijol, Kristensen; Festy (Ferreira 59), Payero, Walace (Samardzic 58), Lovric (Pereyra 72), Kamara (Zemura 72); Thauvin (Success 58), Lucca.
Subs not used: Okoye, Malusa, Guessand, Zarraga, Ake, Tikvic, Camara, Pafundi.
Coach: Sottil.
Referee: MANGANIELLO.
Assistants: MASTRODONATO, YOSHIKAWA.
Fourth official: MARINELLI.
VAR: DI MARTINO.
VAR assistant: MARINI.
Added time: 3+3 minutes.
Possession: 66%-34%.
Corners: 8-4.
Booked: Perez, Simeone.