At the 56th and 55th Olympiads (572 BC and 568 BC), the winner of the Pankration event — the ancient equivalent of MMA/NHB — was an the ancient martial artist Arrhichion. In 564 BC, while defending his crown, he was slain by a competitor whose name does not survive. But apparently, because Arrhichion died after tapping his opponent and did not himself tap, Arrichion was granted the posthumous victory — thus becoming literally dead but not defeated.
To me it sounds like he was killed by a Rear Naked Choke, but you be the judge:
“Accordingly the antagonist of Arrichion, having already clinched him around the middle, thought to kill him; already he had wound his forearm about the other’s throat to shut off the breathing, while, pressing his legs on the groins and winding his feet one inside each knee of his adversary…”