It will be recalled that this will not be the first time the Cagliari fans will be mocking players.

Lukaku endured monkey chants as he stepped up to the spot to take the penalty won by Stefano Sensi midway through the second half.

The striker paused and stared out at the fans after hitting the spot-kick, which he sent past Robin Olsen to re-establish Inter’s advantage.

It is yet another incident involving the Cagliari fans, who have been accused by multiple black players in recent years of hurling racist abuse.

Last season Moise Kean had a similar reaction to the Cagliari fans when he stared at the supporters following his goal for Juventus in a victory at the Sardegna Arena.

Kean came in for criticism from Leonardo Bonucci at the time, though he was backed by team-mate Blaise Matuidi.

Matuidi himself had been subject to racist taunts from Cagliari fans the year before.