Reigning champions Inter came through what was supposed to be a tough test at the Stadio Olimpico with flying colours and are three points off the Scudetto pace with a game in hand.
Substitute Zaniolo decided a hard-fought encounter in Sardinia by stroking home Raoul Bellanova's cut-back in the 66th minute and moving Atalanta five points clear.
Edoardo Bove has had a defibrillator fitted after the Fiorentina midfielder's on-pitch cardiac arrest earlier this month, according to widespread Italian media reports on Tuesday.
Fiorentina earlier remained on Napoli's heels after their 1-0 home win over Cagliari in their first league match since midfielder Edoardo Bove's sudden collapse last weekend.
Edoardo Bove is conscious and alert in hospital after his sudden collapse which caused Fiorentina's match with Inter Milan to be called off, the Serie A club said on Monday.
Fiorentina's Serie A match with Inter Milan was stopped on Sunday after midfielder Edoardo Bove suddenly collapsed to the ground.
"It's too early to talk about the title. All we can do is look out for how we develop as a team, work to improve and win every match we play. But now is not the moment to talk about the title," said Lukaku.
Juventus remain the only unbeaten side in Serie A but their seventh draw of the season means they remain sixth in the standings and are now three points behind leaders Inter Milan. Milan stay seventh, six points behind Juve, though they have played one game fewer.
Simone Inzaghi's side are provisionally ahead of Napoli after netting all five of their goals in the opening 45 minutes at the Stadio Bentegodi through a Marcus Thuram brace and further strikes from Joaquin Correa, Stefan de Vrij and Yann Bisseck.
Juventus signed Brazil midfielder Douglas Luiz from Aston Villa in a deal worth a reported £42.3 million ($53.5 million) on Sunday.
Napoli insisted on Monday Khvicha Kvaratskhelia is not for sale as the star Georgian winger's agent pushes for a move away from the Serie A club, reportedly to Paris Saint-Germain.
Former Chelsea and Tottenham coach Antonio Conte was hired by Napoli on Wednesday as the deposed Serie A champions try to bounce back from their disastrous league title defence.
The 37-year-old Giroud leaves as a big fan favourite and will be remembered in particular for scoring key goals in Milan's 2022 Serie A triumph, the only trophy he won in his three years in Italy.
Paolo Montero will take charge of Serie A side Juventus for the remainder of the season, the club said on Sunday following the dismissal of Massimiliano Allegri.
Massimiliano Allegri was sacked by Juventus on Friday after exploding with anger during his team's midweek Italian Cup triumph.
Olivier Giroud confirmed on Monday that he will leave AC Milan at the end of the season to end his long career in Major League Soccer.
Maria Sole Ferrieri Caputi was assisted by Tiziana Trasciatti and Francesca Di Monte and she was kept bus
Stefano Pioli is close to guaranteeing Milan, in second, a spot in Europe's top club competition in what will almost certainly be his final season at the club
"Now, I feel like crying because we worked so hard, suffered so much, we deserved this joy," the 26-year-old told DAZN.
