Romelu Lukaku was subjected to racist chants by Cagliari fans prior to scoring the game-winning goal from the spot in a 2-1 Inter victory.
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.
Former Pescara midfielder Sulley Muntari also claimed to have been subjected to racist chants by Cagliari fans during a match in 2017.
After the match, Inter defender Milan Skriniar confirmed Lukaku had been subject to abuse, telling reporters he told the Cagliari fans to be quiet.
“I heard things that I think should not exist in football, so I told the Cagliari fans to shut up,” Skriniar told Mediaset Sport. “But now we don't think about it."
Head coach Antonio Conte claimed not to hear the chants, but said Italy has to improve in how fans treat opposition players.
"I can't comment on the episode because I did not hear it," Conte said. “Having said that, we need to improve a great deal in Italy and be more respectful to people who are working, in general.
“When I was working abroad, the fans would cheer on their own team, not spend their entire time insulting the opponent.”
Lukaku has hit the ground running in Serie A, having made the £74 million ($90m) move from Manchester United in August.
The Belgian has now scored two goals in two games as Inter have made a perfect start to life under new coach Conte with wins over Lecce and Cagliari.