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 Post reports.

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.

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Steve Shepherd, a world champion kickboxer, was limping to his car last week when a mugger hit him in the head with a bottle and demanded his cellphone

Gym owner Steve, pictured left, had even been wearing a t-shirt which read '5x World Champion, Steve Shepherd's Palm Beach KickBox-SuperFIT' on the back when he was attacked by the suspect, pictured right

Bystanders, who confused it for a street fight, stepped in and the man, who appeared to be in his 20s, escaped.

Shepherd, who was inducted into the Palm Beach County Sports Hall of Fame and owns a boxing gym, suffered a ruptured eardrum, a cut and bruises.

He told The Sun Sentinel and WPTV: 'All of a sudden, bam. He started yelling at me, "Give me your effing phone".

'His ribs were exposed and so I hit him in the ribs. I heard it crack and he dropped. I'm sure I broke his ribs. I could hear it almost.

'My claim to fame is I beat the guy who knocked out Mike Tyson. What he learned was he picked on the wrong guy. I kind of feel sorry for him.

'Maybe it'll make people 50 and older feel a little less old and feel a little more useful.'

Steve suffered a ruptured eardrum, a cut and bruises during the attack

Steve is training for a fight in March which would make him the 'oldest professional fighter'

Steve owns KickBox-SuperFIT with his brother Ed and has been fighting since 1975

The Palm Beach Sheriff's Office say they are still looking for the suspect who had dark, long hair and had prowled the area for hours, seeking a victim.

They say surveillance footage showed him 'pacing back and forth in a nearby alleyway for a few hours, apparently waiting to mug someone'.

Steve is training for a fight in March which would make him the 'oldest professional fighter', according to reports.