The guitar will be auctioned on May 29 at the Hard Rock Cafe in New York
Dries Mertens, Jose Maria Callejon and Amin Younes all found the back of the net to put Gennaro Gattuso's side on 45 points from 28 games, three points adrift of fifth-placed AS Roma who lost 2-0 at AC Milan earlier on Sunday.
SPAL equalised in the first half through Andrea Petagna but they could not sustain the pace at the San Paolo.
They are now bottom of the table on 18 points, eight points from the safety zone with 10 games left.
Mertens opened the scoring after four minutes, slipping the ball under goalkeeper Karlo Letica after being played through by Fabian Ruiz.
Petagna made it 1-1 in the 29th minute by beating keeper Alex Meret with a low shot, SPAL's first attempt of the game, only for Napoli to regain the advantage through Callejon after he was set up by Eljif Elmas.
The hosts had a third goal disallowed after VAR ruled that Mertens was offside when he crossed for Lorenzo Insigne on the stroke of halftime.
Younes put the result beyond doubt when he headed the ball home from Ruiz's perfect cross in the 78th minute.
SPAL next host Milan while Napoli, already guaranteed a place in the Europa League thanks to their Coppa Italia triumph, travel to in-form Atalanta, who are fourth on 57 points and occupy the last Champions League qualifying spot.
The guitar will be auctioned on May 29 at the Hard Rock Cafe in New York
Fitness enthusiast Sarah Lindsay shares insights on what it takes to embark on a fitness journey and sustain it amidst a busy lifestyle
Such platforms help women to re-enter the workforce by equipping them with new-age skills, upskilling, polishing their interviewing skills and revamping their resumes
Official autism-friendly in-flight certification is in the works, possibly used by other airlines
Airlines cut more than half of their normal flight schedules at Paris's two main airports, with many flights in the southern city of Marseille also grounded
This success was underpinned by a robust 19% growth in total income
The group’s asset base surpassed Dh900 billion
Saji first took the exam in January and scored 99.99 but, because he was not satisfied, he sat for the test again in April