A thug who was seen hitting an OAP was dealt a swift dose of karma when a passerby knocked him out.

The shocking footage shows a pensioner hitting a young man on the pavement with a shopping bag.

He responds by punching the elderly man in the face, who struggles to stand after the blow.

As the other person gears up for a follow-up attack, a burly onlooker charges towards him.

The stocky man floors his rival with a single right hook and then stands over him yelling.

Refusing to give up, his rival gets back to his feet and the pair square up once more.

The thug punching the elderly man in the street
The thug punching the elderly man in the street

The onlooker throws two more jabs and a third right hand which sends his counterpart crashing to the ground again apparently knocked out.

It ends with other witnesses pulling away the larger man.

The shocking incident happened in the city of Rosario in the north-eastern Argentine province of Santa Fe.

More than 400,000 people have seen the clip since it was shared to Facebook.

An onlooker flooring the man after witnessing the fight
An onlooker soon floored the man after witnessing the fight

According to local media, no one has filed a complaint with the authorities and no arrests have been made.

It is unclear whether the police are investigating the incident and what caused the young man to hit the OAP and why the burly man intervened.

The footage comes after a brawl erupted in London between women.

The pair only stopped punching lumps out of one another to tell the large crowd that had gathered to film and photograph the fight that they were all “c***s”.