When three armed robbers showed up to rob a bookmaker in Ireland, they definitely weren't expecting 83-year-old Dennis O'Connor to be as much trouble as he was.

The great-grandfather briefly grapples with and overpowers one of the hammer-wielding assailants. Another robber, armed with a shotgun, points the weapon in his face, but Dennis doesn't even flinch as he holds his ground, leading to a hasty retreat by the robbers.