An unflappable Lucas Herbert led his home Australian Open at the halfway mark on Friday as fan favourite Cameron Smith tumbled down the leaderboard with a poor back nine at Kingston Heath.

Lucas Herbert leads the Australian Open with a 14-under total, as he stays ahead of American Ryggs Johnston. Cameron Smith struggles, finishing even-par. South Korean amateur Yang Hyo-jin leads the women's event by one stroke,

Lucas Herbert is threatening to run away with the Stonehaven Cup following an extraordinary second-round collapse from his superstar LIV Golf teammate Cameron Smith.