There is a runner on third with two out. Batter hits a slow roller to first base. First baseman charges and picks up the ball. Runner from third crosses home. First baseman tags the runner running from home to first, does the run count ?
The run does not count. According to MLB rules:
Since the batter-runner does not make it to first base safely, the run does not count. Similar to a force out.
In English. All base runners that need beat a force play need to reach their base for the run to score.
The last time that the Cubs won a world series came down to this rule.
Fred Merkle did not run from 1st to 2nd and what looked like the winning run scored but because he ran to the dugout instead the ball was retrieved and he was called out.
Its forever known as Merkle's boner.
That game was won by the Cubs who won the League by a game and went on to win the World Series