Ireland have never been in this position before. Not during or before my time. As Grand Slam champions in 2009, the Lions took most of us to South Africa, so this is a chance to plant a flag on the summit – Southern Hemisphere series victory – no other Irish side has reached.

Johnny Sexton said it best on the Stade de France pitch in February. Defeat in Paris would have derailed everything Ireland are working towards. Sydney presents another pivotal moment.

Sexton, Conor Murray, Rob Kearney and Cian Healy were part of the 2013 Lions squad that won a Test series in Australia. Their Ireland now seek that accolade, the difference being no actual trophy. Okay, the Lansdowne Cup but completing the greatest season in Irish rugby history hardly lacks tangible motivation.

Instead there is a set of goals that drive this group. We are not privy to them but we could be about to see how effective they can be.

Middle of summer, with Twickenham and Bilbao past, and every piece of silverware captured, how deep can they dig under the leadership of Sexton and Peter O’Mahony?

O’Mahony’s breakdown response to David Pocock is an encouraging indicator.

Momentarily stepping away from the Test series, it looks like the Wallabies are benefiting from Brad Thorn’s early work with the Queensland Reds. Nowhere near the ripple effect caused by Stuart Lancaster at Leinster, but both coaches are helping individuals reach another level come the international windows.

Michael Cheika is benefiting from the culture Thorn is driving at the Reds, as a salient Australian problem for over a decade is being slowly addressed; the hardening of their pack. Cheika, in turn, has poured a steady stream of powerful Polynesian props and hookers into his squad.

Day one training under Cheika back in 2005 he spoke about hardening up the Leinster tight five. Anyone lacking a tough edge was ruthlessly cut loose.

Working daily with the former All Black and Leinster lock should accelerate the process. Thorn’s first season at the Reds didn’t go well but he wasted no time removing Quade Cooper from the roster.

Ruthless environment Behaviour drives culture and as talented as he is Thorn knows the power of unity.

Cheika would understand. The Wallaby scrum, as a direct result, has hurt Ireland over the past two weekends. We are told Seán Cronin was sacrificed after the first Test for this very reason.

It is also worth noting that Joe rarely reassures a player in the media, regardless of their perceived importance, preferring to keep everyone on their toes. Not a feeling I miss these days.

Rugby, viewed from inside the camp, is a ruthless environment. As supporters, sitting comfortably on our couches, we can only learn from watching the games. So long as Rory Best is fit and captaining the side, it is hard to see past Cronin as reserve hooker. No one else offers that dynamic alternative for the last 20 minutes.

For all we know this is part of the masterplan (maybe Seán will start, thereby completing the full rotation of hookers come the third Test).

What we can be certain about is Joe Schmidt has a plan. The coaches didn’t break bread Tuesday before the first Test saying, “Shall we give Joey a run at 10?’ Every line-up, every tactic you and me can imagine – and a few we can’t – has been meticulously debated and mapped since St Patrick’s Day. Schmidt doesn’t take many days off. The 4am emails his assistant coaches joke about indicate he doesn’t sleep much either.

Like any good coach, he wants to be swayed by performances and results but there was a clear idea, with contingencies included, for this three-Test series. That means the freshest, fittest players will take the field on Saturday, allied by a bench that is primed to finish the Wallabies off.

Resources are stretched for both sides (Dan Leavy, Will Genia etc) but Schmidt has spent three years rebuilding a squad to make certain players are interchangeable come this very moment. He can alter almost every position and still offer similar threats.

Australia are locked into certain players (Israel Folau obviously and an unbalanced backrow that sacrifices a blindside to use Pocock and Hooper). That’s the difference. In a one-off game it is irrelevant but I don’t think Cheika can make more than two or three changes.

Inside centre There lies the state of our national team: no glaring problems entering a World Cup season. Just decisions.

Injury has allowed Schmidt avoid a key selection until now: Bundee Aki or Robbie Henshaw may force a positional switch, certainly longer term, with Garry Ringrose’s excellence meaning all three of them may well be fitted into the team, eventually.

Now that Joey Carbery has joined Munster maybe Henshaw will find himself returning to an old position in years to come.

Watching Henshaw at inside centre I keep seeing his naturally creative elements subdued. In the same breadth he fulfils the set-up element of this position superbly. He still possesses all the gifts – see the pass he ripped off for Jordan Larmour – so while the more prescribed way Ireland play hides his talent, it wins big games.

So nobody can really complain.

Ringrose is so comfortable at Test level now, defending space intuitively and almost always having time in possession, there is a flow to how he carries and passes, like when he put Tadhg Furlong over the gainline. If he can straighten up with a little step we’ll see a clean break or an offload to put somebody away.

During the Six Nations, Aki looked comfortable at second receiver, distributing out the back, a tactic Robbie wasn’t asked to do in Melbourne.

Henshaw, ironically enough, could enter his prime years as a fullback. You want your best players on the field. The midfield that starts in Sydney may tell us more.