~に打ち勝つ (overcome, triumph over)

The compound verb 打ち勝つ, fusing 打つ ('strike') + 勝つ ('win'), meaning 'to overcome, triumph over, defeat.' Takes に for the target of overcoming. The 打ち~ prefix often acts as a strengthener rather than literal striking; also in 打ち消す, 打ち合わせる.