Sporting an intimidating Mohawk and billed as "The Beverly Hills Kid," Osbourne knocked out his opponent, a 38-year-old former champ called "The Man" in 3 minutes, 8 seconds, the London Sun said.
Osbourne had four weeks to prepare in a muaythai kickbox camp, a tough regime that included coffee enemas. He said he was "mentally and physically prepared."
Parents Ozzy And Sharon flew to Pattaya to cheer him on.
Jack said, "Mum and Dad were cool about it."