A short video has emerged on Twitter that appears to show a Millwall supporter punching a Tottenham fan following the FA Cup match between the two sides, which Spurs won 6-0.

The seven-second video appears to have been recorded after the match, with a man wearing a flat-cap assaulting two Tottenham supporters singing an anti-Millwall song.

The thug approaches the two men singing before punching one of them in the face, with enough force to knock the man to the ground.

The man who throws the punch then quickly re-joins the throng of Millwall supporters leaving the ground.

The Twitter user who posted the video to the social media platform claims that the man who punched the Tottenham fan was a Millwall supporter.

The video has already been viewed thousands of times and the Metropolitan Police has confirmed that they are aware of the footage, with several members of the public reporting the video to them.

Violence had already flared between the two sets of supporters ahead of kick-off, with fans clashing ahead of kick-off.

Police in riot gear had to separate fans outside the stadium, as flares and coins were thrown.

Hundreds of police officers meanwhile patrolled the streets around the stadium, while inside White Hart Lane all stewards were instructed to wear plastic hard hats.

Supporters clash ahead of Tottenham's FA Cup match against Millwall Show all 10 1 /10 Supporters clash ahead of Tottenham's FA Cup match against Millwall Supporters clash ahead of Tottenham's FA Cup match against Millwall Trouble flares between Spurs and Millwall fans There was a heavy police presence at White Hart Lane ahead of the FA Cup match between Tottenham and Millwall. AFP/Getty Images Supporters clash ahead of Tottenham's FA Cup match against Millwall Trouble flares between Spurs and Millwall fans Millwall fans arrived at the ground surrounded by police. AFP/Getty Images Supporters clash ahead of Tottenham's FA Cup match against Millwall Trouble flares between Spurs and Millwall fans Hundreds of police officers lined the streets. Getty Images Supporters clash ahead of Tottenham's FA Cup match against Millwall Trouble flares between Spurs and Millwall fans A video later emerged online purportedly showing one Spurs fan being punched in the face by a Millwall supporter. AFP/Getty Images Supporters clash ahead of Tottenham's FA Cup match against Millwall Trouble flares between Spurs and Millwall fans The London derby took place amid a backdrop of heavy police presence. Getty Images Supporters clash ahead of Tottenham's FA Cup match against Millwall Trouble flares between Spurs and Millwall fans A flare is let off outside the stadium. Getty Images Supporters clash ahead of Tottenham's FA Cup match against Millwall Trouble flares between Spurs and Millwall fans The Metropolitan Police helped the match to pass without serious incident. Getty Images Supporters clash ahead of Tottenham's FA Cup match against Millwall Trouble flares between Spurs and Millwall fans Inside White Hart Lane, all stewards wore plastic hard hats. Getty Images Supporters clash ahead of Tottenham's FA Cup match against Millwall Trouble flares between Spurs and Millwall fans Millwall sold out their ticket allocation for the match in minutes. AFP/Getty Images Supporters clash ahead of Tottenham's FA Cup match against Millwall Trouble flares between Spurs and Millwall fans And the game was marred by racist abuse directed at Spurs forward Son Heung-min. Getty Images

Racist chanting directed from the travelling support to Spurs forward Son Heung-min had earlier overshadowed the match, with Millwall manager Neil Harris quick to condemn the abuse.

Son scored a hat-trick at White Hart Lane as Spurs thrashed the Lions 6-0, but their victory was marred by abusive songs aimed at the South Korean from the visiting supporters.

Millwall fans were heard chanting "DVD" and "You're selling three for a fiver" at Son during the first half, thought to be in reference to the racist stereotype of traders selling bootleg copies of films.

Flares were let off outside the ground before kick-off (Getty) (Getty Images)

Son delivered the perfect response with his treble while further goals from Christian Eriksen, Dele Alli and Vincent Janssen secured an emphatic success for Mauricio Pochettino's team.

Harris admitted after the match he had not been aware of the chants but said they would be a blot on Millwall's excellent run in the competition.

"I didn't hear anything, but the club, we won't condone that," Harris said.

Tottenham 6 Millwall 0 player ratings Show all 22 1 /22 Tottenham 6 Millwall 0 player ratings Tottenham 6 Millwall 0 player ratings Michel Vorm – 5 out of 10 It was a quiet day at the office for the keeper due to very few attempts from the Millwall forwards. Getty Images Tottenham 6 Millwall 0 player ratings Eric Dier – 6 out of 10 Had a relatively straight forward day at the back, with few very Millwall moves causing him an issue. Getty Images Tottenham 6 Millwall 0 player ratings Toby Alderweireld – 6 out of 10 A disciplined display from the central defender. Did his job and held his shape at the back. Getty Images Tottenham 6 Millwall 0 player ratings Jan Vertonghen – 6 out of 10 Defended bravely and began moves from the back. Read the game well. Getty Images Tottenham 6 Millwall 0 player ratings Kieran Trippier – 7 out of 10 His assist for Son’s goal was sublime, as were the rest of his deliveries into the danger zones throughout. Getty Images Tottenham 6 Millwall 0 player ratings Victor Wanyama – 6 out of 10 Battled throughout and was a key element to Tottenham’s moves going forward. Getty Images Tottenham 6 Millwall 0 player ratings Harry Winks – 7 out of 10 Oozes confidence for a young lad and it was good to see taking shots on goal. Tottenham Hotspur FC via Getty I Tottenham 6 Millwall 0 player ratings Ben Davies – 7 out of 10 Was charging up and down the wings, which provided Spurs with the width that they required. Tottenham Hotspur FC via Getty I Tottenham 6 Millwall 0 player ratings Son Heung-min – 9 out of 10 The hat-trick hero was on fire today. His movement, work rate and finishing were all spot on. Tottenham Hotspur FC via Getty I Tottenham 6 Millwall 0 player ratings Dele Alli – 7 out of 10 His goal marked his 16th of the season. His positioning was spot on today and he was always making space going forward. Tottenham Hotspur FC via Getty I Tottenham 6 Millwall 0 player ratings Harry Kane – N/A Went off in the early stages of the game after losing his balance and appearing to injure his ankle. AFP/Getty Tottenham 6 Millwall 0 player ratings Tom King – 3 out of 10 Made a handful of important saves, but it’s never a good day when you concede six. Tottenham Hotspur FC via Getty I Tottenham 6 Millwall 0 player ratings Shaun Cummings – 4 out of 10 Defended very narrowly, which allowed Spurs to cause damage in the wide areas. AFP/Getty Images Tottenham 6 Millwall 0 player ratings Byron Webster – 5 out of 10 Struggled to cope with Tottenham's pace going forward. CameraSport via Getty Images Tottenham 6 Millwall 0 player ratings Jake Cooper – 5 out of 10 Heung min-son made his life very difficult. AFP/Getty Images Tottenham 6 Millwall 0 player ratings Tony Craig – 5 out of 10 Defended bravely, but simply failed to contain the Spurs strikers. Getty Images Tottenham 6 Millwall 0 player ratings Jed Wallace – 6 out of 10 He tracked back and worked hard defensively, but failed to show any ability going forward. Getty Images Tottenham 6 Millwall 0 player ratings Ben Thompson – 5 out of 10 Lost the battle in the midfield and this allowed the opponents to dominate the play. Getty Images Tottenham 6 Millwall 0 player ratings Shaun Williams – 6 out of 10 His deliveries up the field were impressive, but they lacked the final product. Tottenham Hotspur FC via Getty I Tottenham 6 Millwall 0 player ratings Aiden O’Brien – 5 out of 10 Was forced to drop deep due to the quality of the Spurs defence. He was marked out of the game. AFP/Getty Images Tottenham 6 Millwall 0 player ratings Lee Gregory – 6 out of 10 His work rate was faultless, but he did not have enough time on the ball to actually make an impact. Getty Images Tottenham 6 Millwall 0 player ratings Steve Morison – 6 out of 10 Looked the most dangerous prospect for Millwall going forward. Getty Images

"We came here in the right spirit, to enjoy an FA Cup quarter-final, so if that's proven to have been to the detriment to the competition then I'm sure it will be left to the authorities. We just want people to enjoy the game.

"Of course it's a shame, for both of us - Mauricio wants to be talking about his team's quality.