I do not see where Tyson was "stunned" I see where he was hit with a good shot and immediately threw punches back and came forward, but there was no hurt or stun about it. [YT]zEV1SMJvCFU[/YT]
He was never seriously stunned but it was a big shot that sent Tyson back. The camera is on his back so it's hard to tell, but he is sent back pretty violently by a big shot, pretty impressive he went back to business.