If the home team

On August 25, 2011 the New York Yankees became the first team to hit three grand slams in one game vs the Oakland A's. The Yankees eventually went on to win the game 22–9, after trailing 7-1.
Walk-off home run
Main article: Walk-off home run

A walk-off home run is a home run hit by the home team in the bottom of the ninth inning, any extra inning, or other scheduled final inning, which gives the home team the lead and thereby ends the game. The term is attributed to Hall of Fame relief pitcher Dennis Eckersley,[4] so named because after the run is scored, the players can "walk off" the field.

Two World Series have ended via the "walk-off" home run. The first was the 1960 World Series when Bill Mazeroski of the Pittsburgh Pirates hit a 9th inning solo home run in the 7th game of the series off New York Yankees pitcher Ralph Terry to give the Pirates the World Championship. The second time was the 1993 World Series when Joe Carter of the Toronto Blue Jays hit a 9th inning 3-run home run off Philadelphia Phillies pitcher Mitch Williams in Game 6 of the series, to help the Toronto Blue Jays capture their second World Series Championship in a row.

Such a home run can also be called a "sudden death" or "sudden victory" home run. That usage has lessened as "walk-off home run" has gained favor. Along with Mazeroski's 1960 shot, the most famous walk-off or sudden-death homer would probably be the "Shot Heard 'Round the World" hit by Bobby Thomson to win the 1951 National League pennant for the New York Giants.

A walk-off home run over the fence is an exception to baseball's one run rule. Normally if the home team is tied or behind in the ninth or extra innings the game ends as soon as the home team scores enough runs to achieve a lead. If the home team has two outs in the inning, the game will officially end either the moment the batter successfully reaches 1st base or the moment the runner touches home plate - whichever happens last. However, this is superseded by the "ground rule", which provides automatic doubles (when a ball-in-play hits the ground first then leaves the playing field) and home runs (when a ball-in-play leaves the playing field without ever touching the ground). In the latter case, all base runners including the batter are allowed to cross the plate.
Lead-off home run

A lead-off home run is a home run hit by the first batter of a team, the leadoff hitter of the first inning of the game. In MLB, Rickey Henderson holds the record with 81 lead-off home runs. Craig Biggio holds the National League record with 53, second overall to Henderson.[5]