Emmanuel Gyasi was left unmarked to finish off a counter-attack and score a stoppage-time winner for Spezia, who moved six points clear of the drop zone.

That came moments after a potential winner from Junior Messias was disallowed for Milan because the referee whistled for a foul on Rossoneri forward Ante Rebic in the build-up just as he was passing the ball to set up his teammate.

Referee Marco Serra quickly held his hands up in an apparent apology to Milan's protesting players but still refused to allow the goal, assigning Milan a free kick instead.

Spezia goalkeeper Ivan Provedel then made a leaping save to stop the free kick from Zlatan Ibrahimovic.

Seconds later, the Provedel denied Ibrahimovic by deflecting the 40-year-old forward's header away off the crossbar.

Kevin Agudelo equalised for Spezia midway through the second half after an opener from Rafael Leao just before the break.

Leao's goal came moments after Theo Hernandez missed a penalty kick for Milan with a poor effort that went wide right.

Milan remained two points behind city rivals Inter Milan, who have a game in hand, and are two points ahead of third-placed Napoli, who beat Bologna 2-0.

Mexico international Hirving Lozano scored both goals for the visitors in Bologna, his first coming on 20 minutes before he finished off a counter-attack from close range two minutes into the second half.

Meanwhile, Cristiano Biraghi scored twice from free kicks in Fiorentina's 6-0 drubbing of relegation-threatened Genoa 6-0.

Dusan Vlahovic had an early Panenka penalty attempt saved before scoring his 17th goal of the season to return to the top the league chart alongside Lazio's Ciro Immobile.

The Viola moved up to sixth place.

It was Genoa's first game since firing Andriy Shevchenko as coach.

This is one of two rounds in Serie A with a maximum attendance of 5,000 fans at matches in a measure aimed at containing the coronavirus.

Australian Associated Press