ガチンコ勝負で始まる言葉

ガチンコしょうぶ【ガチンコ勝負［対決］】

a do-or-die contest; a confrontation [face-off] one puts 「everything one has got [all one's might...

ガチンコしょうぶをする【ガチンコ勝負をする】

battle with ((an opponent)) 「in earnest [wholeheartedly/with everything one's got]