Watch: 90th minute bullet header has blown the Serie A title race wide open
Juventus boss Massimiliano Allegri has targeted next Saturday's Derby d'Italia date with Inter Milan as the "decisive" fixture after Napoli beat the leaders to reignite the Serie A title race.
The Azzurri were four points behind Juve ahead of Sunday's showdown at Allianz Stadium, but they emerged triumphant and slashed the gap thanks to Kalidou Koulibaly's late headed goal in a 1-0 victory.
While Juve will manage to toast a seventh straight Scudetto if they can win their last four games, their run-in looks tricky, with Inter and Roma providing opposition in the league, while AC Milan await in the Coppa Italia final.
Allegri bemoaned a performance devoid of attacking nous from his Bianconeri, quickly turning his attention to next weekend's trip to San Siro.
He said at his post-match press conference: "It was a very bad match for both teams, with practically zero shots on goal. We did what we could and come the end it looked like we would have to draw.
"Unfortunately we did not mark properly for their corner and so we conceded a goal.
"It was a head-to-head clash and Napoli did what they had to do, they kept the ball better and so congratulations to them for that.
"Now, for us, Saturday's match against Inter is the really decisive one.
"We still lead the championship, we have two games at home and two away, but the decisive one will be in Milan.
"Now we have to get over this defeat and get back to work immediately."
Colombian winger Juan Cuadrado added: "We have to keep going right to end and find our groove heading into this last month. We still have a point advantage and it all depends on us."
Napoli do not have the distraction of a cup final and their route to the end of the league campaign takes in games against inconsistent sides Torino and Sampdoria, and lowly Crotone.
But the next appointment will be tough and head coach Maurizio Sarri said: "Tonight we will enjoy this splendid victory. But from tomorrow we will have to start worrying about Fiorentina."
Forward Lorenzo Insigne told sscnapoli.it: "It was an extremely important victory, which we deserved.
"We prepared very well for the match and trained so that we would play a perfect game. It was a display of great sacrifice and effort.
"We took charge of proceedings and got our reward right at the death, but in a legitimate way."