Hamsik struck twice as Edinson Cavani had a hand in three to see off Bologna.
Napoli got off to the perfect start with a goal inside two minutes. Having already threatened through Edinson Cavani, they had no time at all to wait before Maggio headed in a right wing cross from seven yards.
Ezequiel Lavezzi was running wild in the early stages, and when he got away down the left he was caught in two minds as to whether to shoot or pass and ended up letting Emiliano Viviano and the Felsinei off the hook.
The closest the visitors managed to come in the opening quarter was when Marco Di Vaio’s left foot effort was blocked by the legs of Hugo Campagnaro. Soon after the Partenopei had to make the first change of the game when Paolo Cannavaro finally succumbed to a thigh strain which had troubled him over a 10 minute period and was replaced by Sanchez Cribari.
The lead could easily have been doubled on 32 minutes when Cavani was sent clean through just six yards from goal, but Viviano beat him to the bouncing ball just in the nick of time. But again the chance had served only as a warning as the second goal soon followed.
Cavani jumped on a defensive error by Miguel Angel Britos to advance down the right before pulling the ball back to the edge of the box, where Marek Hamsik took one touch before firing a left-footed shot which cannoned off the retreating Britos and looped over Viviano into the net.
Bologna made two changes at half-time, replacing Gyorgy Garics and Henry Gimenez with Luca Siligardi and Riccardo Meggiorini, but it did nothing to stop Napoli repeating their first half trick of adding an early goal.
Campagnaro went forward for a corner but scuffed his near post effort into the path of Lavezzi, who in turn found Hamsik at the far post, the Slovakian having the easiest of tasks to tap the ball into the gaping net to make it 3-0.
Lavezzi had a couple more forays forward before the spirited visitors grabbed a deserved lifeline. Matteo Rubin’s perfect swinging cross found Riccardo Meggiorini, who rose above Andrea Dossena to give Bologna hope with 22 minutes remaining.It could have been 3-2 moments later when Siligardi shot straight at De Sanctis, but Napoli were still showing signs of vulnerability as Alberto Malesani’s men had their tails up. But it turned out the the fightback was shortlived as sub Jose Sosa reached the byeline on 74 minutes and pulled back for Cavani to finally find the net with a sidefoot finish to add to his two earlier assists.