American football
In NFL football, if the game is tied after the four quarters, the two teams compete in at least one more 15-minute period called overtime. During overtime, the first team to score points is usually the winner. However, under the current rules, first used for the 2011 postseason, if the team that has the ball first ends its possession by scoring a field goal, the other team has a chance to score. If that team does not score, or if it scores a touchdown, the game ends. If it scores a field goal, the game continues, and the next team to score wins. During the regular season, only one overtime period is played—if neither team scores, or if both teams score field goals when they first have the ball, the game ends in a tie. During the playoffs, the game will continue with as many overtime periods as needed to decide a winner. If the game is tied after each team has had the ball once in overtime, the first team to score wins.