Senegal worldwide Kalidou Koulibaly was allegedly the subject of racist chants during Napoli's loss to Inter at San Siro on Boxing Day.
Koulibaly has received support from several high-profile Serie A players, including Cristiano Ronaldo, and shortly after Inter's ban was revealed, Icardi offered his own backing to the Napoli defender.
A host of other famous names and faces also showed their support, including Juventus' 5-time Ballon d'Or victor Cristiano Ronaldo, who posted to Instagram: "In the world and in football I always want education and respect". "No to racism or any other type of offence and discrimination!".
After the game, his manager Carlo Ancelotti was particularly angry, especially at the refusal of his continuous requests to stop the game on the back of the repeated racist abuse. The chants intensified when the 27-year-old was sent off with ten minutes to go in the match for sarcastically clapping the referee.
Inter were ordered to play their next two Serie A matches behind closed doors.
"We asked three times for some action to be taken, but the match continued".
Ole Gunnar Solskjær expects flak from former Manchester United players
The 1999 treble victor was in charge of his first match in the Red Devils' 5-1 spanking of his former side Cardiff City . The French forward scored the goal of the game in Man United's 5-1 win in Wales.
"The next time we'll stop playing, even if we lose the match", Ancelotti said.
Koulibaly himself has made a statement on Twitter saying, "I'm proud of the colour of my skin".
Meanwhile, an Inter Milan fan has died after he was struck by a vehicle during clashes with Napoli supporters outside Milan's San Siro stadium. I think in Italy we can do something more for this problem'.
"Clearly, we have to work better on these situations, as we had so many chances to kill off the game and didn't take them", said the former AS Roma and Zenit St Petersburg coach.
"You can't die for a football game", said far-right Interior Minister Matteo Salvini, adding that he would summon fan organisations for talks in January.
Italian football federation president Gabriele Gravina said the incidents that occurred inside and outside the stadium were "no longer tolerable" and that he intends to simplify the rules for suspending matches.