Napoli moved provisionally nine points clear at the top of Serie A on Tuesday by beating Empoli 2-0 to claim their 10th straight league win.
Hirving Lozano's 69th-minute spot-kick and a neat late finish from Piotr Zielinski ensured hosts Napoli made their way past a resilient Empoli side and moved further ahead of AC Milan.
"The road ahead is still long and there are many pitfalls. We need to stay at it and be aware of the importance of the challenges ahead of us," said coach Luciano Spalletti to DAZN.
Champions Milan are at winless Cremonese in Tuesday's late match knowing anything but a victory will leave unbeaten Napoli with an ominous lead on the rest of the league heading into the final matches of 2022 this weekend.
Milan are without suspended stars Olivier Giroud and Theo Hernandez and a clutch of injured players at Cremonese, who sit just inside the relegation zone.
Empoli, who finished with 10 men as Sebastiano Luperto picked up a second booking shortly after Lozano's goal, stay 14th and seven points above the relegation zone.
The Tuscans beat Napoli twice last season and all-but ended their title challenge in April when they came back from two goals behind to stun Spalletti's side.
And on Tuesday they frustrated Napoli, who were without injured wing wizard Khvicha Kvaratskhelia, for large periods of the match.
Napoli were awarded their soft penalty after Razvan Marin was judged to have fouled Victor Osimhen, five minutes after the Nigeria striker had headed over the home side's only previous real chance.
"I'd rather not talk about the penalty," Empoli coach Paolo Zanetti said later.
"The contact didn't seem that obvious as to be a penalty but the referee saw it that way and there's nothing we can do about it."
Luperto's sending off effectively ended Empoli's challenge and Zielinski sent the Stadio Maradona into party mode with two minutes left when he perfectly met Lozano's cross with a first-time strike which opened his league account for the campaign.
Udinese's slump in results continued after drawing 1-1 at Spezia, their fifth draw in a six-match winless run which has left them eighth ahead of their trip to Napoli on Saturday.