Running out the clock
In American football, each quarter of a game is measured with a 15-minute game clock, or 12-minute clock in many high school football codes and the German Football League. A team in possession of the lead and the ball will attempt to use up as much of the game clock as possible in order to bring the game to an end more quickly, thus denying the opposition another chance on offense.
Tiebreaker
In the National Football League of professional American football, if both teams are tied at the end of regulation, an overtime period is played under modified "sudden death" rules. Before the 2017 season, this period was 15 minutes in all games. Since 2017, a 15-minute period has been used only in playoff games (in which a winner "must" be decided); overtime in preseason and regular-season games consists of a 10-minute period. If the team that receives the ball first scores a field goal, then the opponent must receive a chance at equalising that score of their own; the first team to score a touchdown or safety wins the game; and once both teams have had possession of the ball in overtime, the first team to score under any legal means, touchdown (offensive or defensive), field goal or safety, wins. If neither team scores before the end of the overtime period, or both teams score one field goal each, the game is considered a draw and ends, and counts as a "half-win" in the standings for purposes of winning percentage for both draft order and playoff positioning. However, in the playoffs, true sudden death rules apply from double overtime onwards.