I never lost a test match at Murrayfield, but I always wondered if Scotland ever got themselves a genuine Test standard outhalf would results down through the years have gone the other way?

Since the arrival of David Humphreys, Ireland have had a succession of quality operators wearing number 10.

Scotland have not. In the face of Ronan O’Gara then Johnny Sexton, there was Dan Parks, Chris Paterson, Ruaridh Jackson and Duncan Weir.

All capable professionals, with moments of brilliance, but in comparison to Humphs, Rog and Johnny they consistently came up short.

Finn Russell is the difference between this Scotland team and the sides Ireland have consistently beaten since the 1990s.

Paddy Jackson has made a massive leap in quality and maturity as a player since his 2013 experience in Edinburgh, yet all the lessons learned last season - especially in South Africa - will be required this weekend.

Because Russell is a genuine attacking threat. The Glasgow outhalf brings the ball to the line and has been showing enough game intelligence to make the correct decision under pressure.

He can offload and possesses a trademark chip but it’s his tendency to do the right thing in possession which instils confidence in those around him.

Stuart Hogg and Russell exist on the same wavelength. The fullback feeds off his club outhalf as much as Russell seeks to put Hogg in space. Or use him as an elaborate decoy to spring Mark Bennett or, as we saw in November, Huw Jones (The South African based centre should be running with the Glasgow pair on a regular basis from next season).

The Scottish wingers - Tim Visser and Sean Maitland - are powerful strike runners who feed off Hogg’s line breaks while Vern Cotter has a decent collection of centres who can all punch holes.

Like most Scottish sides before them, they seek to attack at pace.

Now, imagine those teams with O’Gara or Sexton at the helm for a decade. They could easily have a far better Six Nations record.

You cannot underestimate the impact a keystone player - like Rog or Johnny or Russell - has on every facet of a squad. They literally drive a team forward, their presence brings calmness.

Johnny’s calf injury puts Jackson under the microscope but he knows this sort of pressure and has coped with it before. Still, it levels the scales in this fixture for the first time in almost two decades. I still feel Ireland will win because they will be prepared for the main Scottish threats.

Nearly every Scottish attack revolves around Hogg and Russell. Much of their play is predicated upon Glasgow’s style. That will probably increase when Gregor Townsend replaces Cotter as head coach this summer.

Townsend must see himself in Russell, in the sense that he’s a fly-half who plays what is in front of him, and is allowed to do so by club and country.

If Russell is unable to release Hogg or another player, because the defence presses up too fast, then he tends to chip into the space behind, either for himself or an outside back. He does this in almost every game for Glasgow. He has the skill set to make the bounce work in his favour even if the opposition know what’s coming. He proved as much with that lovely try against Australia in November.

When Greig Laidlaw hits Russell off the lineout he is ten metres behind the gainline. After shaping to pass Russell carries, bringing his backline with him, so when the ball leaves his foot he is already over the gainline.

The dummy and carry means Russell remains a threat to the defence, as he fixes Australian eyes in the wrong direction before dropping the ball onto his foot a split second later.

The open side winger, Henry Speight, should be covering the space in behind but by holding possession Russell brought him up a yard or two which allowed Huw Jones latch onto the ball and sprint away.

Israel Folau is not out of position but Speight is taken out of the move by his inability to reverse his momentum. That slight pause by Russell completely takes a key defender out of the equation.

This is off the training field. It’s how Russell gets quick ball to Hogg, Jones or the other quality finishers when he gets clean ruck ball or off the set piece.

Scotland are also an ambitious team in the wide channel, five metres in from touch, in contrast to Ireland who strive to get in off the touchline at all costs, whereas the Scots risk being bundled out of play in search of the spectacular.

It leads to tries but it can be shutdown. Andy Farrell’s defence will seek to punish any adventurism.

Another primary weapon, which Ireland learned last year, is the Hogg counter-attack. His brilliant try in Dublin came directly off Conor Murray’s relieving box kick from just outside the Ireland 22.

Murray’s kick was ten metres too long but it’s worth noting that since then the Munster scrumhalf has taken all aspects of his game, including this, to another level (which prompted Glasgow to target his standing leg in the Champions Cup).

Again, this try was before Farrell took control of the Irish defence but Hogg will seek to do exactly the same on Saturday when Murray inevitably kicks to their back field.

Hogg scanned the defensive line, spying where Mike Ross and Rory Best were positioned in this unusually disjointed kick chase. He has the rare gift of doing this almost subconsciously. Keith Earls can’t get near him (momentum, again, working against the turning defender).

Besides the kick being too long, thereby compelling Hogg to run, there is a disjoint in the chase between Simon Zebo, Donnacha Ryan and Dev Toner.

A safe enough assumption is Hogg’s counter attacking will have been examined in minutiae by Ireland. Farrell will have them ready for every possibility.

What if the kick hangs a little longer, if the chase is purer and the midfield defence clogs up to deny a clean break?

Australia provided that answer in November. The game was 40 seconds old when Will Genia box kicked from the exact same position as Murray.

Genia was only two or three metres too long so Russell was forced to rush into Wallaby territory to catch the ball just as Haylett-Petty arrived to tackle him. Russell bounced off him and turned, knowing precisely where Hogg was waiting to attack.

Like against Ireland, Hogg is faced by a prop and a hooker in midfield but it’s a more organised Wallaby defence so he feints to carry before reverting to Plan B.

Hogg switched into play maker mode as Ryan Wilson, the number eight, runs a straight decoy line to fix the midfield and Alex Dunbar arrived from deep in the outside centre channel. Hogg, like Sexton always does, stayed alive by running an escort line that cleverly blocked Reece Hodge from tackling Dunbar.

Australia scrambled back and only conceded three points but the Scottish intent was obvious to see.

That 23-22 defeat was not unlike what Ireland experienced against New Zealand in 2013. The value of such an experience, as we saw in the 2014 Six Nations, can prove enormous.

Outside the camp it was seen as a national (sporting) disaster but for us it was just a setback that we harnessed to move forward and win the championship in Paris.

Ideally, Scotland won’t come out of the embryonic stages of their development on Saturday.

I’m sure they are tweaking this broken field attack to add another dimension that Ireland are not ready for while Farrell and Joe are in the Carton bunker trying to second guess them.

What we do know about Ireland from November is the players are better at problem solving during matches than ever before.

What Schmidt and his coaches will have highlighted is the potential to exploit the poor defensive reads which led to Wallaby tries.

Take the first try by Reece Hodge. For all the encouraging attacking signs from Huw Jones, he was badly exposed here (in fairness, it was his second cap).

If Jones made a decision and hit Bernard Foley, after he received the return ball from Folau on the loop, then the disguised pass to the blindside winger (Haylett-Petty) would be shutdown, forcing Foley to throw a longer higher pass to Reece. That would have gifted Scotland the scope to slow the attack.

Instead, Jones made no decision and was forced to backtrack as Haylett-Petty arrived at pace. Alex Dunbar eventually made a tackle on Hodge as he crossed the Scottish try line that he could have been made20 metres up field.

And still Scotland did enough to win this game. They were leading 22-16 with five minutes to play and Australia down to 14 men.

But it all fell asunder after Russell’s defensive error. The Scottish forwards had just ruined the Wallabies lineout maul, forcing Stephen Moore to shovel ball back to Nick Phipps who put Foley under enormous pressure.

Russell rushed up and hit his opposite number but Foley got the ball away to Tevita Kuridrani. Three missed tackles later, Folau was waiting for the offload anyway, and Australia escaped Murrayfield with the win.

Besides that poor decision at a key moment, Russell’s presence takes Scotland to a different level. Whether they can match Ireland, led by Jackson, will be revealed on Saturday.

What we do know is this Irish squad are less reliant on individuals than in previous seasons. That’s just part of their evolution.

Scotland are not there yet but they could be in a place where losing at home to another major rugby nation has become unacceptable.

Makes for a fascinating tactical duel.