In sports, "luck" is a loaded term.
Many sports fans don't like to admit that sheer good or bad luck can affect the outcome of a game, or of a season. That's particularly true of fans of teams that have benefited from good luck -- don't you dare suggest that their team isn't all that good and has just been lucky. But it also seems to be true of teams that are the victims of bad luck. When a team plays six games that go down to the wire and loses all six of them, some fans want to treat that as an indictment of the team for their inability to win close games, never admitting that such a string could just be a matter of luck.