Juventus coach Massimiliano Allegri said winger Douglas Costa faces a fine after he was sent off for spitting at Sassuolo's Federico Di Francesco on Sunday.

The incident marred a 2-1 Serie A win in which Cristiano Ronaldo scored his first goals for the club. Allegri was also angry at the way his team played after going 2-0 ahead in the 65th minute of the game, saying they became too individualistic.

Costa was dismissed for spitting at Di Francesco after a running feud in which the Brazilian also elbowed and head-butted the Sassuolo player.

"Even if he was fouled, these episodes must not happen," Allegri told reporters. "We mustn't fall for provocation.

"The game was winding down, we had it in the bag and, instead, we stopped playing as a team, everyone wanted to dribble a bit.

"Then the other team gets back into the game, some players get irritated and that sort of thing happens."

Allegri added: "It's only right that [Costa] is fined, and he certainly will be ... I was surprised by his reaction. We have suffered a goal, a red card and a suspension which will be long."

Giuesppe Pecoraro, who works as a prosecutor for the Italian Football Federation (FIGC) has confirmed Costa entire conduct will be monitored -- so any ban would incorporate the elbow and head-butt.

"Starting from the elbow, the Juventus' players behaviour will be look at as a whole with television evidence," Pecoraro is quoted as saying in Ansa.

It is likely any punishment will be announced on Tuesday, but he could face anything up to a 10-game suspension as spitting is categorised as "violent conduct" in the Serie A rulebook.

Juventus are likely to impose a fine of their own following whatever punishment is handed out by the FIGC.

Brazil international Costa apologised for his behaviour in an Instagram post after the match which read: "I would like to apologise to all Juventus fans for this misleading reaction in today's game. I also apologise to my teammates, who are always with me in the good and the bad times.

"It was disgusting and I am aware of this and I apologise to everybody for this. I'd like to emphasise that this isolated incident does not correspond with what I have always shown throughout my career."

Former Juventus defender Patrice Evra replied to Costa's post by saying: "You know that the symbol of Juventus is a zebra and not a llama. You've apologised for what you did, but people will never know what he said to you..."

The Bianconeri have won their first four Serie A games and will now turn their attention to their first Champions League group-stage game, which will be away against Valencia on Wednesday.