Napoli's 18-game unbeaten streak in all competitions came to an end after they lost 3-2 at Bologna in a nail-biting contest at the Stadio Renato Dall'Ara.
Mattia Destro's brace either side of Luca Rossettini's first-half goal looked to have put the game to bed but Gonzalo Higuain scored two goals in the final three minutes of normal time to set up a tense finish.
However the hosts held on to move up to 15th while Napoli missed the opportunity to leapfrog Inter Milan at the top of the Serie A table, and dropped to third after Fiorentina trounced Udinese 3-0 at the Stadio Artemio Franchi.
Napoli's defeat earlier on Sunday left them vulnerable to being leapfrogged by La Viola, who duly obliged thanks to goals from Milan Badelj, Josip Ilicic and Gonzalo Rodriguez.
Ten-man Atalanta humbled Palermo 3-0 at home, in-form striker German Denis grabbing the opener in the 18th minute, before Nicolo Cherubin added a second seven minutes later.
Atalanta did lose Guido Migliaccio to a red card midway through the second half, but quickly made amends as Marten De Roon found the bottom corner with a left-footed screamer.
Luigi Delneri's reign as Hellas Verona boss began as his predecessor Andrea Mandorlini's ended - with a defeat.
Andrea Costa's 61st-minute strike proved enough to earn Empoli a 1-0 victory at the Stadio Marc'Antonio Bentegodi, condemning basement boys Hellas to their ninth loss of the season.
Frosinone wasted an opportunity to climb out of the relegation zone as they lost 2-0 to Chievo.
Palermo's thrashing at Atalanta meant promoted Frosinone would have left the bottom three with victory at the Stadio Matusa, but Chievo struck twice at the death, Alberto Paloschi converting a penalty in the 89th minute and Riccardo Meggiorini converting his team-mate's pass four minutes later.
The Flying Donkeys did lose Simone Pepe to a red card on the stroke of full-time, but Frosinone could not exploit their one-man advantage.
Sassuolo stunned Sampdoria 3-1 at the Stadio Luigi Ferraris to move back into the race for a Europa League place.
Francesco Acerbi opened the scoring with a deflected goal inside eight minutes, before Sergio Floccari tucked away Sime Vrsaljko's cross while goalkeeper Emiliano Viviano was on the ground.
Teenager Lorenzo Pellegrini, 19, made it 3-0 with his first league goal six minutes before half-time, and Samp scored a consolation through Ervin Zukanovic on the stroke of full-time.
In Sunday's late game AC Milan laid siege to Carpi's goal throughout but were forced to settle for a goalless draw that left them in eighth, 10 points behind city rivals Inter.