It means that, in the bigger picture, the result doesn't matter. If, for example, Manchester United are leading the Premier Division table by 12 points, there is only one game to go in the league, then it doesn't matter if they lose, they will still win the league because no other team can beat them even by winning the final game of the season. The maximum number of points available to a team is 3 so no team can catch Manchester United. The result of Manchester United's final match is academic - they have won the league title, no matter what.