Great points, Jawiseman and Zaikesman.
You are a sports guru, Driver.
But, I would like to clue you in on OT in sports which you may not yet be familiar with. There is a buzzer at the end of the games in these sports, but believe it or not, it is possible to play on after the "official end" of the game. A short list would be baseball, basketball, football, hockey, and soccer. You might want check them out sometime, I personally find them quite enjoyable(soccer excepted).
And, many would argue that boxing was more pure, or barbaric - take your pick, when there was no preset number of rounds. The match ended when one person no longer answered the bell at the start of a round.