Ireland completed an outstanding 2017-18 season with a series win in Australia, edging the third and final Test 20-16 at Allianz Stadium.
Joe Schmidt's side claimed a Six Nations Grand Slam earlier this year, with their only defeat of the campaign coming in the opening match of this tour.
And Ireland turned the series on its head with victory in Sydney on Saturday, as they followed up a first away win over the Wallabies since 1979 by scraping through a tough contest decided again by the influential boot of Johnny Sexton.
Captains Michael Hooper and Peter O'Mahony were both injured in a scrappy first half that included two yellow cards, but the 15 points secured by Sexton either side of tries from CJ Stander and Marika Koroibete proved crucial.
A blood-and-thunder start saw Sexton, the match-winner in Melbourne, and Bernard Foley kick the first points at either end, before Australia lost Hooper to injury.
David Pocock, Hooper's back-row partner, continued to keep Ireland at bay and the visitors were dealt a blow of their own when Jacob Stockdale was sent to the sin bin after a TMO review, having shoved his forearm into Nick Phipps' neck.
Foley dispatched the consequent penalty, yet it was Schmidt's men who piled on the pressure in Stockdale's absence - roared forward by the travelling support - and Sexton's kick levelled the match again.
A Wallabies yellow card followed when Israel Folau tugged O'Mahony down in the air - forcing the Ireland skipper out of the game, too - and Sexton's boot delivered another three points when an offside player prevented a try shortly afterwards.
Two more penalties were traded in the first half, before the visitors' momentum finally produced a try shortly after the restart. Stander got the ball down as Ireland surged over from a lineout.
Australia belatedly pushed for a try of their own and it swiftly arrived as Foley threaded a grubber kick through for Koroibete to muscle his way across the line.
The Wallabies then enjoyed an extended spell of pressure as they looked to overturn a one-point deficit, but Ireland held firm and Sexton put away another penalty to force the hosts to chase a try in the final 60 seconds.
One last attack ended with Foley passing the ball out of play and, after a tense wait for a verdict on a possible Stockdale knock-on, the visiting players could celebrate a famous win.