YOU SAID:

I played a game once. I would have won if I didn't lose.

INTO JAPANESE

私は一度ゲームをしました。負けなかったら勝っていただろう。

BACK INTO ENGLISH

I played the game once. If we hadn't lost, we would have won.

INTO JAPANESE

私は一度ゲームをしました。負けていなかったら勝っていただろう。

BACK INTO ENGLISH

I played the game once. If we hadn't lost, we would have won.