Take football as an example. If both sides play, the winner will get 3 points, the loser will get 0 points, and both sides will get 1 point in a draw. Goal difference refers to the number of goals scored MINUS the number of goals conceded (opponents' goals), such as 5: 2, then the winner's goal difference is 3 and the loser's goal difference is -3. This is your goal difference -7: it means that he lost seven more goals than he scored.