In a game of badminton, the aim of the players is to win a fixed number of games, usually, it's a best of three match. Each game is played till a side reaches 21 points first. Each time a rally is won by a particular side, points are scored and they get the right to serve. The side which reaches 21 points first, wins the game. A game must be won with a difference of at least two points. In case the score is tied at 20-20, it's called a deuce. The game continues until a side gets a two point advantage.