The Game -- Accused of Unleashing Mike Tyson Fist in a Hollywood Basketbrawl

Well, that didn't take long -- one week after The Game got Mike Tyson tatted on his hand ... he allegedly decked someone so hard during a basketball game ... police were called to the scene.

Law enforcement sources tell TMZ ... Game was playing in a Pro-Am game Sunday at Hollywood High School when he got into a heated argument with another player. We're told the player says Game threatened to kill him, punched him in the face and took off.

Officers responded and the alleged victim filed a report. Police are investigating the incident as a battery.

We've reached out to Game ... no word back. Ditto for Tyson.