expression, ichidan verb
retaliate; strike back; get one's own back
Idiomatic expression often used when someone who has been defeated or criticized manages to land a small counterblow or retort, even if they cannot win overall.
彼は議論で負けたが、最後に一矢報いる発言をした。
He lost the argument, but he got in a retaliatory remark at the end.
チームは大敗したが、終盤に一矢報いるゴールを決めた。
The team suffered a crushing defeat, but they scored a consolation goal late in the game.