In a game against the Chicago Cubs on September 23, 1908, Fred Merkle of the New York Giants failed to touch second base while running the bases on a game-winning hit by Al Bridwell to score Moose McCormick from third base. As a result, a force out was ruled at second base, and the game was called as a tie. In spite of numerous appeals, the ruling was upheld.
Later that season, the Cubs and Giants were tied with a record of 98-55 for the season. In a makeup game to determine the NL pennant winner, the Cubs beat the Giants 4-2, and went on to become World Series champions.
Fred Merkle (Wikimedia Commons)