A decision by the video assistant referee (VAR) to overturn a SPAL goal and give a penalty to Fiorentina was pivotal as the Viola went on to secure a 4-1 away win at the Stadio Paolo Mazza on Sunday.
The score was tied at 1-1 with 13 minutes remaining thanks to first half goals from SPAL striker Andrea Petagna and Fiorentina's Edmilson Fernandes, when the home side thought they had taken the lead through Mattia Valoti from a counterattack.
However, a VAR review led to referee Luca Pairetto viewing...
Second-placed Napoli wasted half a dozen clearcut chances as they were held 0-0 at Fiorentina in Serie A on Saturday, their fourth successive away game in all competitions without scoring.
Napoli, whose hopes of winning the title last season effectively ended with a 3-0 defeat in the same fixture, were left eight points behind leaders Juventus who visit Sassuolo on Sunday.
"I would say they are two points lost, we played well and it was not the right result," Napoli coach Carlo Ancelotti said.