When Ireland were at their Grand Slam-winning best last year, a key component of their success was their blitzing defence.
In this column, we have often highlighted the cost of Ireland's narrow defence, but when they get it right, it is easy to see why Andy Farrell-coached teams have enjoyed such big wins against the best teams in the world.
In the interest of fairness and balance, it is important to note that Scotland do not fall into that category, yet they do have enough weapons in the back-line to trouble defences.
Ireland had identified yesterday's World Cup opener from so long out that everything that went on in pre-season could be forgiven.
No one will be getting ahead of themselves just yet, but the giddy excitement has returned on the back of a performance that was Ireland at their stifling, ruthless and clinical best.
Those outside of the country might well point to Scotland's flaws rather than Ireland's strengths, yet the squad's confidence has been restored as they now go full steam ahead towards a potential mouthwatering quarter-final clash against South Africa next month.
Last week, Stuart Hogg epitomised the confident attitude coming out of the Scots' camp when he lauded his side's defensive capabilities.
"We believe defence will win World Cups, and that is something we have been working incredibly hard on since we came together in June," Hogg suggested.
Unfortunately for Scotland and their full-back, it was Ireland who have been fine-tuning their defence to a much, much higher level.
This was another excellent day at the office for Farrell's defence. In the lead-up to the game, the incoming Ireland boss spoke confidently about the improvements that he felt his side had made since they got opened up at an alarming rate against England just a few weeks ago.
Unlike Scotland, the Ireland players backed up what was said.
Knowing that if they were able to shut down Finn Russell, they would nullify Scotland's threat, Ireland cranked up their line speed several notches, which worked to absolute perfection. Russell's influence on the game was non-existent because so often when he got ball in hand, he was smashed by a green jersey.
As per usual, along with the outstanding James Ryan, Bundee Aki set the tone in that regard for the 21 minutes he was on the pitch, and even when he was forced off, Chris Farrell ensured that there was no dip in the line speed as he hammered off the line.
After coming in for plenty of unfair criticism after Twickenham, Stockdale also showed that he is more than capable of putting in a defensive shift.
Strategy The winger's risk-or-reward strategy paid off on several occasions as he shot up off the line.
"They're called a hundred per centers for a reason. I think you have to be one hundred per cent, you can't be 99," Stockdale said.
There were plenty of examples of Ireland's outstanding defensive performance and we have picked out four of them:
1 - Bundee Aki is a big defensive leader for Ireland and he showed why early on with a couple of thumping hits and one brilliant turnover after the impressive Garry Ringrose had made a tackle.
Aki charges off the line (red) and smashes Russell (yellow) who barely has a chance to get his head up and assess the situation.
Bundee Aki shoots up off the line to make a big hit on Finn Russell
2 - Stockdale makes a brave decision to shoot up and make a man-and-ball tackle on Hogg, who knocks on. Those sort of decisions will not always pay off, particularly against better teams, but Stockdale certainly got his reward for the "hundred per centers".
Jacob Stockdale makes a superb read on Stuart Hogg and forces the Scotland full-back to knock the ball on
3 - Late in the game, Stockdale again shows tremendous hunger and desire to get off the line and close down Hogg. The Ulster winger reads the situation from a long way out and again does brilliantly to close down the danger.
This time Garry Ringrose makes the early dart towards Russell with Stockdale again marshalling Hogg on the outside.
"That Scottish team has a lot of threats, we talked about that and worked on that all week. I think our defensive performances have been getting better and better," Iain Henderson maintained.
Ireland looked a more complete team again and as much as four tries to none tells its own story, perhaps Hogg was onto something when he said that a good defence will win this World Cup. They have a long way to go before that but Ireland are believing again on the back of an excellent all-round display.