Manchester United have asked for CCTV footage to try to identify those chanting a controversial song about Romelu Lukaku in the win at Southampton, with a view to taking further action.

The 24-year-old striker continued his fine start to life at United at St Mary's on Saturday afternoon, when his first-half effort was enough to secure a hard-fought Premier League win.

Lukaku has quickly become a fans' favourite, although a song to the tune of the Stone Roses' 'Made of Stone' has caused controversy as it references the size of his manhood - a song anti-discrimination body Kick It Out have called "offensive and discriminatory".

Both club and player urged fans to refrain from chanting the song, but it could be heard in Southampton after he scored in the 20th minute, as were chants of "we'll sing what we want".

A United spokesperson said afterwards: "Manchester United has a zero tolerance stance on offensive chanting and behaviour.

"The club and player have been clear in asking for an end to the chant.

"The club has worked with relevant bodies and supporters groups in trying to eradicate any offensive behaviour and will take further action against individuals if this continues.

"The club is in discussion with the police and has asked for CCTV footage from Southampton and will try to identify those who disrespected the player's wishes not to sing the song."

Hampshire Police had received no complaints over the issue on Saturday night, and had no open log on the incident.

On Thursday, United posted a quote from Lukaku saying "fans have meant well with their songs but let's move on together".

The quotes included "#RespectEachOther" and Kick It Out reacted to the chants re-emerging on Saturday with a statement which read: "Kick It Out is aware of repeated racist chanting by supporters of Manchester United today (23 September).

"Kick It Out would like to reiterate its stance that such behaviour has no place in football. Romelu Lukaku himself has requested that the supporters 'move on' from singing the chant in question and Manchester United now has a responsibility to ensure that the request is complied with.

"If anyone has any evidence of supporters engaging in racist chanting, Kick It Out asks that you report it via the organisation's app, to a steward or to the police.

"Kick It Out notes Manchester United's statement requesting CCTV footage from Southampton and will again be liaising with the club, the FA and the police to identify potential perpetrators and ensure appropriate action is taken."

United manager Jose Mourinho was not keen to discuss the subject before the trip to Southampton and after the game was asked about the subject again.

"I don't understand what the fans sing," he said.

"The only music I understand clearly is one from my opponents when they tell Mourinho to go to a place. That's the only one I understand.

"But the only thing I will say is the fans were amazing, the support amazing from the first to the last minute.

"It's important to have that not when you're winning 3-0 or 4-0 and winning the game, but it's more important when you are defending and are exhausted. The songs? I don't understand them."

Mourinho's club are certainly aware of the matter, though, and were in discussions about a suitable response during the first half at St Mary's.

Earlier this week, United contacted relevant bodies to see whether the song about Lukaku could be categorised as racism by the letter of the law.

Press Association Sport understands stewards were briefed ahead of the Carabao Cup tie with Burton on the song that uses a stereotype about black men, with a pocket of fans on Wednesday chanting about Lukaku but having appeared to tweak the words.

"We'll sing what we want'' would get a heartier rendition against Burton. It is understood there were no arrests or complaints to the Greater Manchester Police that evening.