A mugger who attacked a Florida senior citizen walking with a limp picked on the wrong guy after it turned out his victim was a five-time kickboxing world champion.

Steve Shepherd, 68, was heading to his car in West Palm Beach with a pulled muscle when the suspect hit him on the head with a bottle and demanded his cellphone.

The retired professional boxer passed out but was able to regain consciousness and fight back.

He threw a punch to the attacker's head, and then hit his ribs, The Palm Beach Postreports.

Steve, who has been fighting since 1975, had even been wearing a t-shirt which read '5x World Champion, Steve Shepherd's Palm Beach KickBox-SuperFIT' on the back.