the fifth inning is used as the threshold for an official game. If the visiting team is leading, or the game is tied, the end of the fifth inning marks this point.
Even if the inning being played is not complete? I knew it was 5 but I thought both teams might have had to get a chance to bat in the last inning played....
Note: After 9 innings of play, if the game is called or suspended the score is determined after the last full inning unless the home team scores to tie or takes the lead in the bottom half of the inning, in which case the winner is determined by the score when the game is called. The listed pitchers must start or there is "no action."