Milan - Juventus' bid for an eighth consecutive Serie A title were boosted on Saturday after title-chasing Napoli's ambitions took a knock with a goalless draw against bottom club Chievo.
Carlo Ancelotti's second-placed side needed a win to maintain the six-point gap between them and leaders Juventus, but could not find a way past Chievo in the Stadio San Paulo just days before they host Red Star Belgrade in the Champions League.
Napoli are now eight points behind Juventus, who beat SPAL 2-0 on Saturday with goals from in-form Cristiano Ronaldo and Mario Mandzukic.
"There's no point looking at the Serie A table now. We'll look and evaluate at the halfway point," said Ancelotti.
Inter Milan are a further point back in third following their comfortable 3-0 win over second-from-bottom Frosinone.
Joaquin Correa snatched a last-gasp 1-1 draw with AC Milan for Lazio as both teams lost ground on the top three. The club from the capital are fourth but five points behind Inter, whose local rivals Milan are a further point back in fifth.
Ancelotti's side were frustrated by the side from Verona, who were playing their first game under new coach Domenico Di Carlo. He is their third manager this season after Lorenzo D'Anna was sacked in October and before him, former Italy boss Gian Piero Ventura, who quit after just four games.
"We were too bland in everything we did today - in construction, ball recovery and finishing, which allowed Chievo to play a defensive game," Ancelotti said.
"But it was a good test ahead of Wednesday's match against the Red Star. The tactical theme against Red Star will be the same."
Chievo goalkeeper Stefano Sorrentino pulled off some fine saves, but was largely helped by Napoli's wastefulness in front of goal.
A curling shot from Lorenzo Insigne hit the post after 75 minutes and towering Senegalese defender Kalidou Koulibaly missed a chance to snatch a late winner when his overhead kick from a corner shot flew just wide.
"We've rediscovered the Chievo spirit," said Di Carlo, whose side now have one point from 13 games after being deducted three for false accounting.
Correa rescues Lazio
Correa came off the bench to slot home for Lazio four minutes into added time and cancel out Franck Kessie's deflected 78th-minute opener.
Lazio had dominated the game in the Stadio Olimpico with Milan goalkeeper Gianluigi Donnarumma denying Ciro Immobile and Brazilian Wallace as the visitors struggled in the absence of suspended Argentine striker Gonzalo Higuain.
Lazio's Sergej Milinkovic-Savic netted after 28 minutes but it was ruled offside.
Milan thought they had grabbed the three points when they broke through 12 minutes from time, Kessie beating Lazio goalkeeper Thomas Strakosha with a shot which took a deflection off Wallace.
But Lazio stole a point in the final attack with Correa volleying a low angled shot past Donnarumma.
Mid-table Sampdoria held city rivals Genoa 1-1 in the first derby since the bridge disaster which killed 43 in August.
Fabio Quagliarella headed in for Sampdoria after eight minutes before Poland's Krzysztof Piatek equalised from the spot on 17 minutes, to overtake Ronaldo at the top of the Serie A scorers' list with ten goals.
Earlier Parma, back in Serie A this season for the first time since 2015 after three straight promotions, beat Sassuolo 2-1 to overtake their local rivals in the table and move into the Europa League places in sixth with 20 points.
Gervinho opened the scoring at the Stadio Tardini, with Bruno Alves adding a second after 25 minutes.
Khouma Babacar pulled one back for Sassuolo from the spot after 36 minutes.
Empoli came from two goals down to end Atalanta's four-match winning streak with a last-gasp 3-2 win which moves them out of the relegation zone at the expense of Bologna, who held Fiorentina 0-0.