I agree that 'luck' is only part of the game. If a team is so dominating and outplay his opponent by huge margin, but end up losing to freak goalie's saves and free kick goal by the opposition - shall the team be deemed unlucky and rewarded with points?

Many teams choose to give up the first few cup matches and rest totally for the league. It is only fair that these managers accept whatever results that can come. At the very worst, the team can stall and try to lose by smaller margin instead of risking it in the hope that the opposition will also play weak lineups.