In reality, for such events not to be considered results of luck, they must be replicated at least twice under the same circumstances. Only then may the event be said to require skill.
Dude 2: Can you do it again
Dude 1: Hell Yeah, watch this.....
*doesn't happen rest of game*
Dude 2: Looks like it was just luck, thats the Call of Duty effect for ya.
Dude 1: FFFFFFFFFFFFFFFUUUUUUUUUUUUUUUU!!!!