Lazio climbed to third in Serie A as they won 1-0 at Udinese on Sunday after Inter Milan, with eyes on two cup finals, fielded a weakened side, suffered a first-half red card and lost 3-1 at champions Napoli.
Lazio's veteran striker Ciro Immobile won a 61st-minute penalty for the only goal as Lazio jumped to 68 points two points ahead of Inter and one behind second-placed Juventus, who play Monday. After that, all the contenders have two matches left.
Inter hold the last Champions League spot with a two-point edge over AC Milan.
Napoli continued their Serie A title party with late goals against a shorthanded Inter Milan.
With two finals looming – against Fiorentina in the Italian Cup on Wednesday and Manchester City in the Champions League on June 10 – Inter coach Simone Inzaghi made eight changes from the team that beat AC Milan in the second leg of their European semifinal last Tuesday.
Inter's task became even tougher when veteran centre back Roberto Gagliardini picked up a second yellow card in the 41st minute.
Andre-Frank Zambo Anguissa put Napoli ahead after 67 minutes, spinning and volleying a shot into the corner of the net.
Inzaghi threw on some regular starters and one of them, Denzel Dumfries, set up Romelu Lukaku for a close-range equaliser after 82 minutes.
Napoli skipper Giovanni Di Lorenzo curled a 20-metre shot into the top corner to restore the lead three minutes later.
As Inter pressed desperately, Gianluca Gaetano finished off a Napoli counter-attack with his first league goal for the club deep into added time.
Inter's European chances could be enhanced on Monday when second-placed Juventus face a second Italian Football Federation ruling on illicit transfer activity.
An original 15-point deduction was later revoked by the country's highest sports court.
Juventus then visit Empoli in the last game in the round.
Fiorentina, who also have two cup finals coming up, against West Ham in the Conference League as well as the Italian Cup, drew 1-1 at Torino in the afternoon.
Luka Jovic, who started on the bench, gave Fiorentina the lead but Antonio Sanabria levelled for the hosts.
Cremonese's brief stay in Serie A came to an end when Spezia and Lecce played out a goalless draw.
Lecce on 33 points and Spezia, on 31, are still not safe. Both can be caught by Hellas Verona, currently in the third relegation position, with 30 points and two matches remaining.
Spezia pulled seven clear of Cremonese who return to Serie B after one season in the top flight. Bottom side Sampdoria were already doomed.
Cremonese's fate was effectively sealed on Saturday when they were thrashed 5-1 at home by Bologna.
The first two promotion places to Serie A have been locked up by Frosinone, the Serie B champions, and Genoa.
The third will be the winner of the play-offs, for which six clubs are in the running: Bari, Parma, Cagliari, Sudtirol from Bolzano, Reggina and Venice.