The umpires and their calls, the time of day or night of the game, and strength of schedule are actually all random factors which affect the outcome of a game. Kind of my point. If you had a different umpire in a one run game, with all other things remaining the same, it's very likely that you would have had a different outcome
If a game is won by 5 runs, you can be pretty sure, but not 100% sure, that the random factors were not significant factors in the outcome of the game.
If the game is decided by one run, you can be pretty sure that the random factors played a significant role in the outcome of the game.