Napoli are still in the hunt to retain their Serie A title after the champions beat Scudetto rivals AC Milan 1-0 on Monday.
Matteo Politano came off the bench and lashed home the only goal of the game with 11 minutes remaining in front of delighted fans in Naples as the hosts racked up a fifth straight win.
Napoli leapfrogged Milan into second place but still have a battle on their hands to deny Inter a 21st league crown as they sit seven points off the pace with seven matches remaining.
Antonio Conte's team were superior at the Stadio Diego Armando Maradona, where Politano's second goal of the season decided a largely stodgy contest, not helped by Milan only being able to select star attackers Rafael Leao and Christian Pulisic.
"It's a happy moment for us because we're back in second place. I thanked the boys for what they've done this season as it could have finished badly," said Conte of an injury-ravaged season.
"We've got back to what we're were like last season, we've got to keep going without getting ahead of ourselves."
Milan now trail their local rivals Inter by nine points and will, in all likelihood, have to content themselves with a return to the Champions League.
"I think we're done with the Scudetto race. We're nine behind Inter and Napoli are ahead of us now," said Allegri.
"We've got an advantage of a few points for the Champions League, let's try to keep it that way by winning some matches."
Napoli's win came without Romelu Lukaku, who has incurred the wrath of the club hierarchy after staying in Belgium for treatment of a hip injury, while Denmark striker Rasmus Hojlund was ruled out with a stomach bug.
Winter signing Giovane forced Maignan into the best save of the match in the 50th minute with a stinging drive from distance and there was little more goalmouth action until Politano pounced on Koni De Winter's weak headed clearance with a powerful and decisive first-time finish.
JUVE EYE CHAMPIONS LEAGUE
Juventus moved to within a point of Serie A's Champions League places with a 2-0 win over Genoa, as the top four battle heats up.
Taking advantage of fourth-placed Como's goalless draw at Udinese earlier in the day, Juve notched the three points in Turin thanks to Gleison Bremer's fourth-minute header and a 17th-minute strike from the ever-reliable Weston McKennie.
American McKennie's fine finish took his Serie A tally to five, equalling his best-ever haul in a single league season back in his first campaign with Juve in 2020/21.
But he showed no interest in that personal statistic when speaking with DAZN after the match, saying, "The important thing is getting into the Champions League".
Home fans had to thank goalkeeper Michele Di Gregorio for a superb double save which stopped spirited Genoa from getting back into the game, first pawing away Aaron Martin's penalty and then keeping out Vitinha's volley.
Di Gregorio has had a tough second season at Juve, dropped from the first team in February following a series of clangers and only in goal on Monday due to Mattia Perin being substituted at halftime with a calf injury.
"He has some good moments and some tough moments, but we always knew that he was a quality goalkeeper. He knew that his moment would come," said Bremer.
Di Gregorio's stops helped put some distance between fifth-placed Juve and Roma, who trail Spalletti's team by three points in sixth after being thumped 5-2 at Inter on Sunday.
Juve are also four points ahead of Atalanta, 3-0 winners at Lecce, ahead of Saturday's clash between the pair in Bergamo, with Como hosting Inter the following day.
Genoa suffered no real damage to their bid to avoid relegation as Daniele De Rossi's team sit six points above Lecce, who are in the bottom three after a heavy defeat.
Lecce were booed off by disgruntled fans after a defeat which left their team level on 27 points with Cremonese, who sit just outside the drop zone thanks to their superior head-to-head record.