This Ireland defence are stepping up quicker than you can say "series decider", it's like watching George Graham's Arsenal, and it forces the hosts to kick long.

And then the visitors turn more Harlem Globetrotters when they snaffle the ball back - Rob Kearney flings a pass out the back of his hand in the tackle, before a creative cross-field boot finds Keith Earls on the run before he's gathered in by the retreating Australian defence.

David Pocock, take a bow. He's in there again to get hands on the ball at the breakdown and regain possession for the hosts.

And that brings the biggest cheer of the day from the Sydney crowd.

The Wallabies are having to replace their skipper here, Michael Hooper takes the brunt of a rampaging Tadhg Furlong and will have to go off - Pete Samu the man to come on in his place.

A fumble in the Aussie 22, and that sparks a brief moment of chaos as Ireland sense the opportunity before the scuttling Kurtley Beale picks up and slices a kick into touch.

Tadhg Furlong sticks his head down and rolls forward and now it's Ireland with the momentum 20 metres from the Australian try-line.

David Pocock isn't having any of that. Brilliant turnover from the hosts' number eight.

Samu Kerevi thunders into a sea of green shirts as he takes a crash ball at the side of the scrum, but Australia use it quickly down the blind-side and catch the visitors offside.

Bernard Foley will look to stick this between the pins...

And he does. It's all square.

That's the first time the Australians have looked to stick the ball deep into the Ireland half, and Kurtley Beale finds his mark superbly.

Robbie Henshaw desperately tries to keep it in play, but lands a boot on the whites of the touchline behind his own try-line to hand the Wallabies a scrum.

And now a chance to go for the posts for Johnny Sexton. Israel Folau the offender.

No mistake from the Ireland fly-half, he gets the visitors on the board.

Image source, Getty Images

Cracking feet from Jacob Stockdale, who gets his first chance to run at the Australian defence and the winger side-steps his way beyond several golden shirts.

Ireland lose possession, but it's pulled back for a late hit on Johnny Sexton in the midfield earlier in the move.

The visitors opt to kick to touch.

Image source, Getty Images

The Ireland pack a tad lighter than their Australian counterparts, and it's the hosts who use the ball quickly from their own feed just inside their half.

Adam Coleman carries into the tackle, and back right it goes.

Good, quick ball from the Wallabies but they're struggling to make too much ground and Rob Kearney gobbles up a deft chip kick.

The hosts whip it right through a string of golden hands, but Ireland's scrambling defence is strong and they win the penalty at the breakdown through their skipper, Peter O'Mahony.

Groans from the home fans, high-fives in the Ireland camp.

And here we go.

Can Ireland bring that 39-year wait for a series win in the Southern Hemisphere to an end?

Bernard Foley gets this one under way.

That should get the hairs on the back of your neck standing to attention.

The visitors blare out Ireland's Call, before the Australian national anthem reverberates through the Sydney night as the whole of the Allianz Stadium get to their feet.

Another quick look at the teams before kick-off...

Ireland: Rob Kearney, Keith Earls, Robbie Henshaw, Bundee Aki, Jacob Stockdale; Johnny Sexton, Conor Murray; Jack McGrath, Niall Scannell, Tadhg Furlong, Devin Toner, James Ryan, CJ Stander, Peter O'Mahony (capt), Jack Conan.

Replacements: Cian Healy, John Ryan, Tadhg Beirne, Jordi Murphy, Kieran Marmion, Ross Byrne, Jordan Larmour, Robert Herring.

Australia: Israel Folau, Dane Haylett-Petty, Samu Kerevi, Kurtley Beale, Marika Koroibete; Bernard Foley, Nick Phipps; Scott Sio, Brandon Paenga-Amosa, Sekope Kepu, Izack Rodda, Adam Coleman, Lukhan Tui, Michael Hooper (captain), David Pocock.

Replacements: Tolu Latu, Tom Robertson, Taniela Tupou, Rob Simmons, Ned Hanigan, Pete Samu, Joe Powell, Reece Hodge.

John McEnerney: Sexton to orchestrate things for the Green Machine again & guide us to a series win to put the icing on the cake of a savage historic season for @IrishRugby, external. The BGP’s to put in huge shifts like last week PO’M, CJ, Murray etc. Close enough but history beckons. Green win

Image source, Inpho

Ireland head coach Schmidt believes the injection of Lukhan Tui into the Wallabies back row presents a fresh challenge for the Irish pack.

Tui's inclusion at blindside flanker will add some much-needed strength, but Schmidt highlighted his defence - after a thumping hit on star prop Tadgh Furlong in the second half last week - as an asset which Ireland must nullify.

"I thought Tui did well when he came on [last week]," Schmidt said.

"He does give them a bit more in the line-out whether he comes on loose or whether he plays at lock.

"There was one time where Tadgh Furlong carried and I thought Tui hit him very hard."

Image source, Getty Images

Australia coach Michael Cheika wants to see his side turn on the style against Ireland, and reckons that will be the best way to beat the Six Nations champions.

"You can't win finals without scoring tries and playing footy, I'm a true believer in that," said Cheika.

"They did well last week to restrict us from doing that and we'll be looking to try and open up this week."

Australia 21-26 Ireland:

Andrew Conway and Tadhg Furlong scored Ireland's tries, with Johnny Sexton kicking 16 points as the tourists were rewarded for a dominant performance with a first away victory against the Wallabies since 1979.

Kurtley Beale and Taniela Tupou crossed for the hosts, who were also awarded a penalty try in the first half.

Ireland's victory ended a losing streak of 11 straight Tests against the Wallabies in Australia, keeping them second in the World Rugby rankings.

Australia 18-9 Ireland:

Tries by Bernard Foley and David Pocock helped the Wallabies bring Ireland's 12-game winning run to a halt.

Foley also kicked two penalties and a conversion for the hosts.

Joey Carbery kicked three penalties for the visitors, who had tries by CJ Stander and Kieran Marmion ruled out.

Now then, it's a huge match in Sydney, but how did we get to this series decider?