Ireland centre Garry Ringrose touched down for Ireland's second try of the evening as the side extended their lead against Australia at the Aviva Stadium.
The Leinster back, winning just his third cap, showed great feet to sneak his way between the Aussie defence after reacting well to a lose pass from Conor Murray.
Captain Rory Best had found CJ Stander from a lineout deep inside the Australian 22, with the South African-born flanker taking the ball to ground.
Murray's pass was errant but Ringrose did very well to score his first international try.
Paddy Jackson added the extras to give Ireland a 17-0 lead.
However, there was a sting in the tail for the Irish as the Wallabies crossed for a try of their own in the 39th minute.
Winger Dane Haylett Petty crossed under the post after some great play by his to leave the score 17-7 at the break with all to play for in the second half.