It's no coincidence that during Ireland's impressive run to the top of the world rankings, they've consistently been able to keep 15 players on the field at all times.
Since the 2021 Six Nations Championship in which Ireland picked up two red cards, their discipline, or at the very least their ability to avoid the referees reaching for their pockets, has been exemplary.
Across 15 Tests in that time, Andy Farrell's side have given up just two yellow cards, both coming in this summer's series in New Zealand, with James Ryan and Andrew Porter picking up sin-bins in the second and third Tests respectively.
By contrast, their opponents in that time have picked up a combined 12 yellow and six red cards, and while there's no doubting the steps Ireland have taken with their gameplan in the last 18 months, their discipline has played a major part.
You only have to look back on the last week's World Cup final between New Zealand and England in Auckland to see the impact a red card can have on a game, with England's Lydia Thompson sent off after 18 minutes of the decider, and the Black Ferns coming from 14-0 down in her absence to retain their title.
While last week's thrilling game between France and South Africa was further proof that red cards don't ruin games, there's no doubt that they can change it.
With that in mind, tackle and rucking technique has never been more important.
"We're constant with that," Ireland head coach Andy Farrell said of the emphasis he places on technique in the contact area.
"We know that some teams live on the edge with that stuff and sometimes it falls over the edge, they think that it influences the game.
"We're a little bit different to that, we go hard on discipline.
"We go hard on things that we got away with that we shouldn't have gotten away with.
"So, I think we're realists as far as that's concerned because we want to play the game as it should be played, but we also don't want to give anyone easy outs to the opposition and put pressure on ourselves.
"It's something we've been pretty good at for a decent amount of time now, but keeping that message fresh is super important because of the way the game is at the minute."
It's 15 games since Ireland last picked up a red card in a Test match, dating back to Bundee Aki being sent off for a dangerous tackle in the final round of the 2021 Six Nations against England at the Aviva Stadium, Peter O'Mahony having also received a red during that campaign.
Since then, only France can rival Farrell's side for card-discipline, with just one yellow and one red card in that period, the sending off being that of Antoine Dupont a week ago. Again, it's no coincidence that they have claims on being the world's best.
The numbers would suggest the southern hemisphere sides are struggling desperately to come to grips with their discipline though.
Australia have had 13 cards (12 yellow and one red) in their 12 games in 2022, having had eight yellows and two reds in 2021.
New Zealand and South Africa's inability to keep a full team on the field is similarly bad. This year alone the Springboks have had 10 yellow cards and two reds in their 11 games, with the All Blacks only marginally better - eight yellows and two reds across 12 Tests.
Aki returns to the squad for tomorrow's meeting with Australia, having just served a seven-game ban for another red card - his third in three years - this time while playing for Connacht in the BKT United Rugby Championship in September.
The Connacht centre was able to return for the Wallabies game having completed World Rugby's coaching intervention programme, ensuring the final week of his proposed eight-week ban was quashed.
And Farrell said the centre is constantly working to improve his technique.
"Of course we have chats like, you know? There's nobody more disappointed than him, he doesn't do it on purpose.
"Everyone's different as far as mentality is concerned, we work on all of our players on how to stay calm enough to read the situations better and being able to be aggressive on the back of the decisions that they've made is super important for us rather than just running around, fired up, the whole time.
"The game's changed in that regard, people get it wrong from time to time.
"I don't think we've anyone who has any type of malice in our side that does things intentionally."
COUNTING CARDS - SINCE JUNE 2021
Ireland: 15 games, 2 yellow cards
France: 15 games, 1 yellow, 1 red card
Italy: 13 games, 5 yellows, 1 red card
Scotland: 15 games, 8 yellow cards
England: 15 games, 7 yellows, 1 red card
Wales: 17 games, 11 yellow cards
New Zealand: 26 games, 13 yellows, 3 red cards
South Africa: 24 games, 18 yellows, 2 red cards
Argentina: 23 games, 19 yellows, 2 red cards
Australia: 26 games, 20 yellows, 3 reds
Discipline has been a big issue for tomorrow's opponents Australia this season, as much around their penalty count as their ability to keep players on the pitch.
With 16 penalties conceded in last week's defeat to Italy (above), they're averaging just under 14 penalties per game in 2022, the most of any Tier 1 side.
And while they come into the game with a record of just four wins from 12 games this year, Farrell says their results aren't a true reflection of their performances.
"There is a good majority of our players who have never played against Australia before and don't quite know the mentality of the Australian team. For me, it’s never changed. I’ve had, I’ve played against Australia all my life you know, and I know the mentality, that is 100% where they sit in my mind. It’s exactly where they sit themselves.
"One hundred percent, they’ll think they’re hard done by not to beat New Zealand, and the refereeing decision etc. They know they can beat anyone in world rugby on any given day and that’s why they’re such a threat and when you add to that Dave Rennie, we know what he brings to a team.
"He’s a wise, wise coach that has been around for a long time and won a lot of things. He’s a very shrewd coach and they are very dangerous and it’s a perfect game for us at the weekend."
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