Former Napoli coach Maurizio Sarri reacted with an offensive gesture toward the local fans when Lazio's train arrived in the southern city on Friday.
On Saturday, the bespectacled manager who likes to quote Charles Bukowski made a much bigger impression in his former stadium when he directed Lazio to a 2-1 win that ended Napoli's perfect start to Serie A.
Lazio lost both of their opening matches after finishing second to Napoli last season - albeit 16 points behind the runaway champions.
Sarri, who coached Napoli from 2015-18 for his first job with a major team after decades with provincial clubs, restored a winning mentality to the Partenopei that was crowned when Luciano Spalletti coached Victor Osimhen and Co. to Napoli's first title in more than three decades last season.
Now he's trying to achieve the same thing at Lazio, who last won Serie A nearly a quarter of a century ago.
Sarri also coached Lazio to a win at Stadio Diego Armando Maradona in March - one of only two home losses for Napoli last season.
Luis Alberto and Felipe Anderson were involved in both Lazio goals. First, Luis Alberto put the visitors ahead with a backheel shot after getting set up by Anderson. After the break, Anderson again carried down the right wing before a cross that Luis Alberto's fake left for Daichi Kamada to strike in.
It was Kamada's first goal in Italy after the Japan international joined Lazio from Eintracht Frankfurt.
Piotr Zielinski equalised for Napoli two minutes after Luis Alberto's goal with a deflected shot.
Lazio had two more goals wiped off for offside upon VAR review, and goalkeeper Ivan Provedel palmed a shot from Napoli dribbling wizard Khvicha Kvaratskhelia over the bar early on.
Osimhen, who scored three goals in Napoli's opening two games, threatened only occasionally.
Napoli were three points behind leaders AC Milan, who beat Roma 2-1 on Friday.
Back in Italy after a year with West Ham, Gianluca Scamacca scored twice as Atalanta beat Monza 3-0.
First, Scamacca powered in a towering header, then he fired in from the edge of the area,
Ederson put Atalanta ahead after a setup by Charles De Ketelaere, who was on loan from AC Milan.
Bologna came back from a goal down to beat Claudio Ranieri's Cagliari 2-1, with Giovanni Fabbian scoring the winner in the 89th following an error by goalkeeper Boris Radunovic. It's another positive result for Thiago Motta's Bologna following a draw at Juventus last weekend.
Also, Udinese and promoted Frosinone drew 0-0.