Two kids are playing a game. Right after the game is over one of them shouts happily:
"I won! I won!"
or should he better say "I win! I win!"
As a celebration of winning a game just played, the use of I win is grammatical and probably "more appropriate."
It is common in this context (of right after the game is over) for native speakers to say I win or we win or you win; in this case the act of winning is seen as being in the present.
But since the game play is actually over, I won is also grammatically correct.
The window of time does not last long to say I win in respect to a game just played. Like you said, it has to be right after the game. A person can be in the act of winning only so long. When you pick up the game pieces to start a new round, that moment is pretty much past.
Another use of the present is I win every time we play this game. In this case the present simple describes an ongoing habit. So a person can say this before, during or after a game.
Thank you for your interest in this question.
Because it has attracted low-quality or spam answers that had to be removed, posting an answer now requires 10 reputation on this site (the association bonus does not count).
Would you like to answer one of these unanswered questions instead?