Napoli stole a march on the four clubs vying for a place in the Champions League next season thanks to a 2-0 home win over Palermo at the Stadio San Paolo.
Edinson Cavani put Walter Mazzarri's side in front from the penalty spot and Marek Hamsik added the second 10 minutes before the interval.
Both sides created further chances, but Napoli's win was secured through a well-organised performance with dangerous counter-attacks whereas Palermo spurned their biggest chance due to a lack of concentration.
Napoli now lead Inter Milan, Udinese and Lazio by three points, putting the ball in their court for their matches tomorrow night with the quartet all in the hunt for Serie A's third place in the Champions League next season.
Roma's hopes of playing in Europe next season were left hanging by a thread after they were held to a goalless draw in difficult conditions by Chievo.
The game at the Stadio Marc'Antonio Bentegodi was played under a constant deluge with puddles forming and preventing Luis Enrique's side from playing their preferred flowing football with the ball on the ground.
Chievo had the better chances and had a goal correctly ruled out for offside in the second half of a game which was ruined by the weather.