Napoli delayed Juventus' coronation as Serie A champions for another week at least as a goal in each half from Kalidou Koulibaly helped the Partenopei to a 3-1 win at Chievo.
Juventus could have ended the title race by avoiding defeat at SPAL on Saturday but suffered a shock 2-1 loss, and Napoli closed to within 17 points of their rivals with six matches remaining.
Koulibaly opened the scoring just after the quarter of an hour mark before Arkadiusz Milik's 65th-minute effort gave the visitors a cushion.
Koulibaly made sure there was no way back eight minutes from time before Bostjan Cesar grabbed a late consolation for Chievo.
Third-placed Inter Milan regained their five-point lead over fierce rivals AC Milan after a 3-1 victory at Frosinone, who are now eight points adrift of safety.
Radja Nainggolan struck after 20 minutes and Ivan Perisic scored from the penalty spot in the 38th minute before Francesco Cassata pulled one back just after the hour mark.
Matias Vecino made certain of the win in the closing stages. Sampdoria bounced back from successive losses to Torino and Roma with a 2-0 triumph over 10-man Genoa.
Gregoire Defrel gave Samp a fifth-minute lead before Davide Biraschi was sent off for Genoa shortly after half-time, with Fabio Quagliarella then netting from the penalty spot moments later.
Leonardo Pavoletti bagged a 1-1 draw for Cagliari at Torino in an ill-tempered fixture that saw three players sent off.
Simone Zaza opened the scoring for Torino eight minutes after half-time but was then given his marching orders with a quarter of an hour to go.
Pavoletti equalised almost straight away but Cagliari finished the match with nine men after Luca Pellegrini and Nicolo Barella were sent off in the closing stages.
Bologna moved three points clear of the drop zone after a goalless draw at Fiorentina while the score was identical in the match between Sassuolo and Parma.