American football rules
Super Bowl LI was the first Super Bowl to go into overtime with a 28-all tie between the Atlanta Falcons and New England Patriots, which the Patriots eventually won with James White scoring a touchdown on the Patriots' first drive.
History of the New England Patriots
Despite being the overwhelming favorites in the game, the Patriots failed to protect a four-point lead on a Giants drive late in the fourth quarter. A dramatic pass from Eli Manning to David Tyree put the Giants deep in Patriots territory, and a Manning touchdown pass to Plaxico Buress gave the Giants a 17-14 lead with 35 seconds left. The loss left the 1972 Dolphins as the only undefeated champions in NFL history. The Patriots ended the season at 18–1, becoming one of only three teams to go 18–1 overall, including playoff games, along with the 1984 San Francisco 49ers and the 1985 Chicago Bears, both of whom won their respective Super Bowls (the 1984 49ers won Super Bowl XIX and the 1985 Bears won Super Bowl XX).