Inter Milan's Romelu Lukaku was subjected to racist abuse as he scored a second-half penalty to earn his side a 2-1 victory at Cagliari in Italy's Serie A, Aljazeera reports.

The 26-year-old Belgian striker appeared to be the target of "monkey" chants from the home crowd at the Sardegna Arena as he prepared to take the decisive kick on Sunday.

Lukaku sent goalkeeper Robin Olsen the wrong way with 20 minutes remaining to mark his second goal in as many matches for his new club. The former Manchester United striker turned to glare at the home fans responsible for the taunts.

It was the second racist incident at the Sardegna Arena this year.

Inter coach Antonio Conte called for respect at the post-match press conference.

"I need to be honest with you. I was so focused in the game, so I did not listen any chants against Lukaku," he said on Sunday.

"However, as it happened so many other times, I think in Italy we need to improve a lot. We need to have more education and to have more respect with the people who is working," he added.

"In other countries you support the team, you don't insult the opposition like this. There must be the maximum respect."

Former Juventus forward Moise Kean, who now plays for Britain's Everton, was also on the receiving end of racial abuse by Cagliari fans at the same stadium last season.

The 19-year-old scored was also subjected to racist "monkey" chants in April as he scored in Cagliari for his former team. Serie A did not take action over the incident, saying the "certainly reprehensible" chants had "limited" relevance. 

Juventus midfielder Blaise Matuidi also reported racist abuse from Cagliari fans in 2018, but Serie A said it could not take action because the referee and match observers did not hear it.

On Saturday, Inter Milan fans and observers called for action after the latest incident.

"After racially abusing Moise Keana and Matuidi the last two seasons, Lukaku is the newest victim of ... racist fans in Cagliari," said Twitter user Hash. Serie A "must act", he said. Elliot Hackney, another Twitter user, said the racist chants were an "absolute disgrace".

James Benge called the chants at Sardegna Arena "disgusting" and added: "Cagliari shouldn't have any fans in there again this season."

Inter lead Serie A after two rounds on six points along with Torino and latest champions Juventus, while Cagliari have yet to pick up a point.