in rare form

Prepositional phrase

idiomatic

(idiomatic) Performing very well.

Japanese Meaning

絶好調で、非常に良い状態であるさまを表す。 / 通常以上に調子がよい、元気な状態を表す。

During the championship match, she was in rare form, scoring three goals and dominating the field.

選手権の試合で彼女は絶好調で、3ゴールを決めて試合を支配した。

Sense（1）

(idiomatic) Performing very well.