Napoli beats Lazio 3-0 in battle for Champions League placeAC Milan's Suso celebrates after scoring the opening goal during a Serie A soccer match between AC Milan and Palermo, at the San Siro stadium in Milan, Italy, Sunday, April 9, 2017. (AP Photo/Luca Bruno)
Jose Callejon marked his 200th appearance for Napoli with the opening goal as Maurizio Sarri's team moved seven points clear of fourth-place Lazio.
Napoli remained four points behind second-place Roma, with seven rounds remaining.
''We were aware that today there was a lot at stake,'' Napoli goalkeeper Pepe Reina said. ''Now we're looking ahead and we'll work to try and catch Roma.
''The race is open. We have a difficult fixture list, but we're in good health and we know we can play for it right until the end.''
Lazio was looking to move to within a point of third place and was full of confidence after reaching the Italian Cup final with an aggregate victory over city rival Roma. Napoli had meanwhile lost its semifinal to Juventus.
But it was Napoli that took the lead with one of its trademark team moves. Dries Mertens found Marek Hamsik with a through ball and he crossed for Callejon to tap in at the far post.
Insigne should have doubled Napoli's lead on the stroke of halftime but he curled his shot wide with only the goalkeeper to beat.
However, the Italy international did score six minutes into the second half, finishing off Allan's chipped pass from outside the area.
Lazio coach Simone Inzaghi made a double substitution immediately afterward, bringing on Keita Balde Diao and Wesley Hoedt.
Keita almost scored with his first touch, but was denied by Reina.
Lazio had a series of chances to get back into the game. It went closest in the 71st minute, but Insigne got back to block Patric's shot on the line.
Inisgne finished off the match in style for Napoli with a goal in stoppage time.
''We're fourth in the table and in the Italian Cup final, no one would have predicted that,'' Inzaghi said. ''We faced a great team, we had to be perfect and instead we made some mistakes which our opponents didn't forgive.''
CROTONE 2, INTER MILAN 1
Inter Milan's hopes of qualifying for Europe were dented by a shock defeat at relegation-threatened Crotone.
Inter's dreams of Champions League football next season were already over but it now faces the prospect of failing to qualify for the Europa League following a quick-fire double in the first half from Diego Falcinelli - including a penalty after Gary Medel handled in the area.
Inter has picked up just one point in its three matches since thrashing Atalanta 7-1 and dropped to seventh, two points behind AC Milan and the last qualifying spot for the Europa League. The two Milan teams face off in a derby on Saturday.
''We should have looked at this match with a different mentality, and instead we had the wrong approach,'' Inter coach Stefano Pioli said. ''The season is still long and the chances are not finished. We shouldn't apologize, we just need to react immediately to this awful defeat. If Crotone was an exam, Inter failed.''
Crotone gave itself hope of escaping relegation as it moved to within three points of 17th-placed Empoli with a second successive victory.
''We have a very demanding calendar, but ... we want to be competitive right until the end, with a dream in our hearts,'' said Crotone coach Davide Nicola, who has promised to cycle the 1,300 kilometers (808 miles) from Crotone to Turin if his side avoids the drop.
Danilo D'Ambrosio netted for Inter in the 65th and the Nerazzurri almost leveled but Eder hit the post.
BOLOGNA 0, ROMA 3
Edin Dzeko continued his battle to finish the season as the league's top goalscorer with the third goal in Roma's comfortable victory.
It was Dzeko's 24th Serie A goal this campaign and sees him remain joint top with Torino forward Andrea Belotti, who also scored on Sunday.
Juventus forward Gonzalo Higuain is next with 21 goals.
Federico Fazio and Mohamed Salah were on target in the first half as second-place Roma cut the gap back to six points on leader Juventus.
AC Milan leapfrogged above bitter rival Inter with a comfortable 4-0 victory over Palermo.
Suso came back from injury and scored an early free kick, before setting up Mario Pasalic for Milan's second. Carlos Bacca headed in a third before halftime and Gerard Deulofeu scored after the break.
Palermo defender Giancarlo Gonzalez was sent off following a second booking seven minutes from time.
Fiorentina moved to within five points of a European spot as a last-minute goal saw it snatch a 2-2 draw at Sampdoria.
Elsewhere, Torino came from behind to win 3-2 at Cagliari. Han Kwang-song had become the first North Korean to play in Serie A when he came on for the final four minutes against Palermo last weekend and the 18-year-old netted Cagliari's second in stoppage time.
Udinese beat Genoa 3-0.