ビギナーズラック

noun

beginner's luck

Refers to the phenomenon where a novice unexpectedly succeeds at something, often used in games, sports, or gambling.

• 初はじめてのポーカーで勝かったのは、ビギナーズラックだね。

  Winning at my first poker game was beginner's luck.

• 彼かれのホールインワンはビギナーズラックだった。

  His hole-in-one was beginner's luck.