Roberto Gagliardini (left) of Inter Milan battles for possession with Toma Basic of SS Lazio on January 9, 2022 in Milan, Italy. Photo: VCG

Inter Milan kept their lead in the Serie A title race thanks to a tight 2-1 win over Lazio on Sunday, while Juventus pulled off an incredible comeback to sink a distraught Roma 4-3.

Milan Skriniar thumped home the decisive goal with a towering header from Alessandro Bastoni's cross in the 67th minute to put Inter back one point ahead of AC Milan, who had moved into first place after a 3-0 win at Venezia in Sunday's early match.

Simone Inzaghi's side have a game in hand on their local rivals after their match at Bologna on Thursday was not played due to Covid infections among the opposition squad.

It was a strong display at the San Siro for Inter against Inzaghi's old club, who however gave a good account of themselves and leveled in the 35th minute through Ciro Immobile's 15th league goal of the season after Bastoni had crashed the hosts into the lead with a long-range daisy cutter five minutes before.

Maurizio Sarri's side even gave Inter some scares after Skriniar crashed in his third league goal of the campaign, with Immobile having a goal ruled out for an obvious offside, but they couldn't create anything clear cut and left Milan with their seventh defeat of the season.

Six points behind Inter in third are Napoli, whose faltering Serie A title hopes were kept alive by Andrea Petagna in a 1-0 win over Sampdoria.

Burly forward Petagna struck the winner with an uncharacteristically acrobatic bicycle kick just before halftime to keep Napoli - missing a number of key players to COVID-19 infections and the Africa Cup of Nations - just about in the hunt.

Lazio meanwhile sit eighth, level on 32 points with local rivals Roma who completely fell apart in their loss to Juve, who are three points behind fourth-placed Atalanta in the race for the Champions League after their 6-2 win at virus-hit Udinese.

Deservedly losing 3-1 in the 69th minute and having lost Federico Chiesa to a potentially serious knee injury in the first half, Juve were leading with 76 minutes on the clock at the Stadio Olimpico as Roma collapsed so dramatically that Jose Mourinho openly questioned his players' character.

"It was 70 minutes of complete control... We did very well for 70 minutes, but after that it was a psychological collapse," Mourinho told DAZN.

"When you're in the shit you're supposed to get back up and show what you're made of, but there are people in the changing room here who are a bit too nice, a bit too weak."