Former Serie A referee Gianpaolo Calvarese insists Inter Milan striker Romelu Lukaku should not have been sent off at Juventus.

Lukaku received a second yellow card at the end of the 1-1 draw in the first-leg of their Coppa Italia semifinal for taunting Juve fans amid racist insults being heard from the stands.

Calverese says ref David Massa was wrong with his call, telling Calcio e Finanza: “It's been commented on by pundits and on social media, but we still don't know why exactly Lukaku was sent off.

“We don't know if Massa booked him for putting his finger to his mouth to silence the crowd, and in fact he'd already done the same celebration with his national team too.

“Adding to the confusion is the fact that the booking actually came several seconds after his celebrations, and it was when he was closer to midfield rather than near the penalty area where the celebration actually happened.

“There are two possibility, one would be that he was booked as part of the mass brawl.

“It hardly seemed as though he had done enough to warrant a booking then, however, as he only actually started remonstrating with the referee after he had already been given the second booking.

“More likely is that he was booked for telling the crowd verbally to “silence" themselves, but then how would Massa have heard him?

“There's no way he could have heard [Lukaku's words] if he hadn't heard the racist chants, which he would've been obligated to stop the match if he had been aware of."