勝負だ

let's have a showdown

→ 勝負
phrase Rare #24,662
let's have a showdown A bold, emphatic way to challenge someone to a contest or face-off.
JA: 勝負だ、どっちが先にゴールできるか競おう。
EN: Let's have a showdown—let's see who can reach the finish line first.

勝負だ土地の主!

It's a showdown, Master of the Land!

— Demon Slayer -Kimetsu no Yaiba- The Movie: Mugen Train (2020)

ボブはスケートではきみといい勝負だ。

Bob is about as good as you at skating.

さあバカども勝負だ

Come on, you idiots—let's settle this!

— きっと、うまくいく (2009)

勝負だ

Let's settle this!

— アバウト・タイム ~愛おしい時間について~ (2013)

最後の勝負だ

This is the final showdown.

— 紅の豚 (1992)

勝負だ!

Let's settle this!

— きっと、うまくいく (2009)