Six Nations: Can Scotland's best since '99 beat best Ireland ever?

Brace yourself for a classic. The greatest squad of Scottish players in two decades down one end of Murrayfield on Sunday and the greatest squad of Irish players, well, ever, down the other.

The penultimate round of the Six Nations with so much on the line. Rain forecasted, but no amount of the stuff is likely to douse the fire on the pitch and the atmosphere in the stands.

You can hang your hat on Ireland. We know they'll perform. They're not world number one for nothing.

The utterly compelling factor is Scotland. After two victories and a positive performance in defeat in Paris, is this the day this team truly comes of age? After showing an at times cosmic attacking game, belligerence in defence, resilience in adversity, can Scotland go the extra mile and overturn the best in the world?

Or will it be just another heartache at the hands of a winning machine that has beaten them seven times in a row on an aggregate score of 180 points to 81 and 21 tries to seven? Ireland's average winning margin in these games has been 14. The bookies have them winning by seven.

Whatever way you cut it, Ireland are favourites.

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The stakes haven't been this high for Scotland in the longest time. A Triple Crown on offer in the here and now and a possible tilt at the Six Nations title itself in a week's time (alien territory, that) if they can somehow do what South Africa, Australia and France have failed to do against Andy Farrell's side in the past four months and what New Zealand couldn't do in two out of three Tests last summer.

Given that Scotland have not won a Triple Crown since 1990 or a championship since 1999, you could call Sunday their game of the century. Hyperbole? Not really. Name another time when Scotland got this deep in the Six Nations while retaining a chance of winning the thing. There hasn't been one. Ever.

For Ireland, this is a gargantuan day, too; a chance to go four from four before a Grand Slam match against an out-of-sorts England in Dublin next weekend.

They won Grand Slams in 1948, 2009 and 2018. None of them were secured in Dublin and none of those teams, cherished all, are as good as this current one. They didn't have the depth of class. They didn't have the all-court game. They didn't win a series in New Zealand.

'Scots have caused some palpitations across water'

Every match-up on Sunday is a potential thrill, individually and collectively.

The centurion full-back Stuart Hogg against the planet's pre-eminent man in the 15 jersey, Hugo Keenan. Two lethal midfields. Four in-form wings. The great sorcerer Finn Russell and the master orchestrator Johnny Sexton. Powerful front fives. Scotland's captain and openside Jamie Ritchie and Ireland's world player of the year openside Josh van der Flier. Number eight Jack Dempsey, making his first Six Nations start, going up against Caelan Doris, arguably the player of the series so far.

The whole thing is madly exciting. Paul O'Connell was a big part of Ireland's glorious 2009 vintage and is forwards coach now. If you want an angle on the standards at work in the Irish camp then read the words of the warrior of old.

"We have been good sometimes as a pack and individually," he said after Ireland beat Italy in Rome a fortnight ago. "I don't think for the last two games that 'sometimes' will be good enough. We can't be 'sometimes players' over the next two weeks."

Sometimes players? In round two of the Six Nations, Ireland blew France away in Dublin with an extraordinary performance. They started that Test without Robbie Henshaw, Jamison Gibson-Park, Tadhg Furlong and Dan Sheehan. Forty-five minutes in, they lost Tadhg Beirne through injury. Two minutes later, Sexton went the same way.

Six nailed-on frontliners gone and yet they still won the last half-hour 10-3 and the match 32-19. Five of those six are in the 23 for Sunday.

They controlled every aspect against the reigning Grand Slam champions. They owned the territory battle to such an eye-watering degree that they spent just over nine minutes attacking inside France's 22, while the French managed just 57 seconds in Ireland's. They squeezed the French until the pips flew out.

If Scotland beat them it will be the single most impressive victory since their last championship win almost a quarter of a century ago.

There are some palpitations across the water. Scotland's capacity to create scores from nothing, the cleverness of Huw Jones and Sione Tuipulotu in midfield, the scary running power of Duhan van der Merwe out wide, the vision and execution of Russell - this is a team that takes some amount of analysing.

We saw a new side to Scotland in Paris. At 19-0 it looked like a gruesome day was unfolding, but the way they worked their way back into it, led wonderfully by Russell, was a joy. Over the course of the next hour they outscored France 21-6 in their own place.

Scotland's dominance was astonishing. They scored three tries and should have scored at least two more. When they got it back to 25-21, they looked the likely winner, which was trippy in the circumstances. Their own errors cost them, which was painful because that was an epic win that got away.

Farrell and his on-field leaders have gushed about their opponents this past week, Sexton describing them as the best Scottish team he's seen in his 14 years as a Test player. Fourteen is also the number of times he's played against the Scots, so Sexton is as good an outside observer as you'll find.

After Ireland's victory over France, O'Connell was asked about the yellow card handed out to the colossal Uini Atonio instead of a red (which he deserved and which it was subsequently upgraded to). He went against the national grain when saying that he was glad the prop wasn't sent off. He wanted it to stay 15 v 15. A fair fight.

"I was happy," he said. "You want it hard. The harder it is, the better. You want it to be as hard as possible so that we can learn as much as we can about ourselves."

It's Scotland's job on Sunday to give the big man his wish and then some. If Gregor Townsend's team arrive with all guns blazing, this could be very special indeed.