One second you're standing tall on the playing field, thinking about your next move, and then pop!
The lights blot out, the world swims and all of a sudden, you're horizontal, holding onto the ground for dear life.
What just happened? Well, friend, you just got sucker punched. Pretty damn hard, actually.
It's alright, just keep cool. You'll come around in a bit (probably), and the moron who just jacked you up is getting pulled off into the locker room and will be looking at punishment from the league (maybe).
This kind of scenario plays rather regularly in the world of sports—play gets chippy, athletes get pissed and the next thing you know, someone's swinging at an unsuspecting victim.
The following are some of the cheapest sucker punches out there, where the punches were thrown at individuals who were in no way a danger to those throwing the blows.