The score should not decide whether basic respect survives the game.

Competition gives people permission they would not claim anywhere else. Losing badly or winning easily both loosen something, and behaviour that would be unthinkable at work or at a dinner table becomes normal for ninety minutes. The score is temporary and the way you treated people is what everyone remembers, including the children on the sideline learning what is allowed.

Decide before the next game what you will do at the final whistle regardless of the result. Shake the hand, say the thing, mean it. If you cannot manage it after a loss, that is worth working on.