This is the shocking moment a Chelsea fan was knocked out with a single punch while goading rival West Ham supporters.

The lad was making faces and yelling at Hammers fans before the 1-1 draw at the London Stadium in East London on Saturday afternoon. He appeared to shout 'you're 50 years old' while wagging a finger.

However, a fan with black-rimmed glasses stepped up and knocked out the leery fan with a single punch to his mouth. Fans were chanting 'irons, irons'.

The victim was later seen with his teeth knocked out and blood pouring from his jaw while being wheeled away. He looked sheepish following the hard lesson but appeared to have recovered.

Speaking tonight to ViralPress, onlooker Harry Westgate, a West Ham fan who recorded the incident, said it was 'satisfying see the blue get flopped'.

But he said he was glad the youth was not seriously hurt.

He added: 'He was knocked clean out.'

Local media reported that police are aware of the incident and have been contacted for comment.

The incident happened before kick-off at the London Stadium as fans made their way into the ground. Chelsea opened the scoring before West Ham equalised within the first 30 minutes.

The game finished in a 1-1 draw.