A thug suffered instant karma when he started a fight with a motorist, who turned out to be a hardened Muay Thai boxer.

The local yob squared up to Peerapat Ngamsilapakorn, whom he nearly grazed while allegedly speeding without headlights on in Bangkok, on July 11.

Peerapat's terrified girlfriend tried to defuse tensions as the aggressive man walked up to Peerapat and began spitting insults in his face.

Footage shows the thug throwing the first blow at Peerapat, which he blocked with an arm and backed away, before unleashing a flurry of punches at his outmatched adversary.

The man's earlier bravado was instantly knocked out of him as he fell to the pavement within seconds.

An enraged Peerapat kicked him several times and put him in a headlock before passers-by intervened. He then lodged a report with the Sai Mai Police Station

A police spokesman said: 'The complainant said he was heading to the convenience store and had his turn signal on, but the other man on the motorcycle came without headlights and nearly hit him.

'As seen in the clip, the attacker walked over, started cursing, and threw the first punch. The complainant said he retaliated in self-defence.'

Peerapat said his opponent allegedly threatened him not to press charges, and challenged him to a rematch despite being trounced.

He said: ‘I am a very calm person and never pick a fight with anyone. However, when you were being bold and loud to me, how can I yield? Everyone taught me not to concede easily.

‘I talked with him politely but he refused to listen. I told him to leave, but he refused to go. I could have attacked him first, but it would not have been fair because I know Muay Thai so I let him throw the first punch.

‘After that, it happened as is seen in the video. He talked too much and learned a hard lesson.'

Peerapat said that police were tracking down the thug to be questioned over the road rage incident.