Ring announcer Dan Hennessey is putting down his mic for good ... he says he's done with the gig after he was dragged for declaring the wrong winner at a big fight last weekend in Australia.
The blunder happened on May 11 at the RAC Arena in Perth ... just after Cherneka Johnson and Nina Hughes went toe-to-toe against each other for 10 rounds with the WBA bantamweight belt on the line.
Hennessey read the three judges' scorecards .