A Toledo basketball player turned into a hero during a game last weekend -- performing successful CPR on a referee who had collapsed in the middle of the contest.
The scary incident was caught on video ... when during the Toledo Glass City's game against the Jamestown Jackals on June 11 -- a ref wobbled, and then crumpled to the floor.
You can see in the footage, referee John Sculli lay motionless for several moments ... before Glass City's Myles Copeland raced over to help out.
Copeland -- who's also a firefighter -- told ESPN he didn't feel Sculli's pulse or see him breathing when he got to the man .