Second-placed Napoli cut Juventus's lead at the top of Serie A to two points when Raul Albiol's header gave them a 1-0 win over a defiant Genoa on Sunday.
Milan came from behind to beat Chievo 3-2 in a San Siro thriller and the video assistant referee (VAR) system was involved in three penalty decisions as Fiorentina won 2-1 at Torino with a last-minute spot kick.
Juventus, chasing a seventh successive title, slipped up on Saturday when they drew 0-0 at lowly SPAL, ending a run of 12 successive wins. The Turin side have 75 points from 29 games while Napoli are on 73 with the two sides still to meet at Juventus on April 22.
Roma, who won 2-0 at Crotone with goals in each half from Stephan El Shaarawy and Radja Nainggolan, are a further 14 points back in third.
Napoli struggled to break down Genoa's defence, their intricate moves through the middle of the field often breaking down with the final pass.
Their frustration mounted as Lorenzo Insigne and Dries Mertens both hit the post, before central defender Albiol finally broke the deadlock with a near post header from a corner in the 72nd minute.
VAR INTERVENES
Milan, sixth with 50 points, took an early lead through Hakan Calhanoglu but were stunned when Mariusz Stepinski and Roberto Inglese scored twice in two minutes to put the Flying Donkeys 2-1 up at halftime.
Patrick Cutrone turned in from a rebound to level for Milan, the referee initially disallowing the goal for offside before consulting VAR and changing his mind.
Portugal forward Andre Silva snatched the winner from close range with eight minutes left. There was still time for Franck Kessie to miss a last-minute Milan penalty, awarded for handball with the help of VAR.
The video system was even more in evidence at Torino where Fiorentina had an early penalty revoked after a VAR consultation and then a second penalty awarded for handball -- only for Jordan Veretout's weak effort to be saved by Salvatore Sirigu.
Veretout made amends by giving Fiorentina the lead with a solo goal in the 59th minute before Andrea Belotti volleyed Torino level with four minutes left.
It did not end there as Fiorentina were awarded a third penalty for handball, again with the help of VAR, which Cyril Thereau converted.
Cagliari scored twice in stoppage time, through Leonardo Pavoletti and a Nicolo Barella penalty, to win 2-1 at bottom club Benevento, who had gone in front at the start of the second half with a goal by Enrico Brignola.
Josip Ilicic scored a hat-trick in Atalanta's 5-0 win at lowly Verona in the other game