Kevin-Prince Boateng reckons AC Milan must win at Juventus on Sunday to stand any chance of finishing second in Serie A.
Inter Milan lost 2-0 at Cagliari while Roma picked up a vital three points against Torino in Sunday's Serie A action.
Cagliari made a perfect return to their temporary home in Trieste as Mauricio Pinilla scored twice to down Inter Milan 2-0.
Napoli coach Walter Mazzarri has vowed to cut third-placed AC Milan adrift as the Serie A season nears its finale.
Cagliari defender Francesco Pisano has been ruled out of the rest of the Serie A season after fracturing his fibula.
Napoli kept in touch with Serie A leaders Juventus with a 2-0 win over Genoa, while AC Milan drew 2-2 at Fiorentina.
Cagliari came within inches of victory at Catania, with a 0-0 draw seriously hindering the Sicilians' European hopes.
Lazio and Roma meet in Serie A on Monday both looking to step up their late pursuit of a Champions League place.
Cagliari are looking for a new home after cancelling their contract at the Stadio Is Arenas in Quartu Sant'Elena.
Serie A leaders Juventus won 2-1 away to 10-man Inter Milan on Saturday, while Lazio beat Catania by the same scoreline.