Atalanta showed no signs of rustiness from their 17-day break without a competitive fixture, and La Dea almost made the perfect start after just three minutes. Mario Pašalić’s dissecting through-ball found Aleksei Miranchuk, whose low strike beat Alex Meret before hitting the post.
Napoli saw plenty of the ball following that early let-off and Victor Osimhen nearly struck his first home goal since February when the Nigerian striker attacked Giovanni Di Lorenzo’s hooked cross with a diving header, but Atalanta’s goalkeeper Marco Carnesecchi was equal to the effort.
A cagey contest took hold midway through the first half until the Partenopei’s familiar defensive frailties – leading to no clean sheets in 10 previous matches – surfaced again.
Meret was first at fault for failing to claim Hans Hateboer’s header across goal, allowing Pašalić to cut back to Miranchuk just yards out and the forward made no mistake converting his third Serie A goal of the season.
La Dea were relentless in their pursuit for a second before half time and another defensive error from Juan Jesus gifted the ball to Miranchuk 20 yards out, allowing the Russian playmaker to pick out Gianluca Scamacca, who thumped a decisive finish into the bottom corner past Meret.
In an attempt to kick-start a Napoli comeback, Francesco Calzona made two changes at the break, one of which, Piotr Zieliński, was inches away from making an instant impact by clattering the post with a swerving volley from a tight angle.
The home crowd inside the Stadio Diego Armando Maradona tried to muster some inspiration for their side as Osimhen was presented with two guilt-edged chances late on, yet Napoli’s top scorer couldn’t find a way past the impenetrable Carnesecchi.
Atalanta still had time to punish Napoli for those missed chances with a sweeping counter-attack, finished by Teun Koopmeiners’ driving strike past Meret that nestled into the bottom corner.
Atalanta were ruthless with their chances and Gian Piero Gasperini’s side struck the perfect balance between defence and attack to secure a first SA victory since mid-February.
Napoli’s new manager bounce under Calzona – which led to an initial six-match unbeaten run – comes to a crashing halt against Atalanta and the Partenopei now have their work cut out to secure European football for next season.
Flashscore Man of the Match: Aleksei Miranchuk (Atalanta BC)
