Eleven years and 120 Tests separate James Ryan and Alun Wyn Jones but when the two clash in this afternoon's Six Nations game at the Aviva Stadium (2.15pm kick-off), the watching crowd will be treated to a battle between two of the game's very best second-rows.
As a measure of the 23-year-old's standing in the Irish set-up, witness the IRFU's desire to tie one of their prized assets to a long-term deal this week while the Leinsterman has also been entrusted with a greater leadership role in Andy Farrell's new set-up.
"I've played against him a few times at this stage so maybe it's not as momentous as it would have been the first time I played him," said Ryan of the battle. "But he is certainly amongst the best second-rows in the world.
"I have met him after the games, particularly after the game we lost at the Millennium (last season). I thought he was very gracious how he handled himself after they'd won and we'd lost, I respected that. The way he went about his business was really good.
"He has an insane amount of test caps now, so he's kind of the heartbeat of their team in many ways. Particularly as a forward pack and as a front five, we're going to have to be on the money."
Now in his third Six Nations, Ryan is used to coming up against the likes of Jones and, in a wider sense, more used to all that is involved in representing Ireland.
"It's not laid back, but maybe I don't have as much nervous energy as I would have had this time two years ago.
"I would have been very nervous. Getting up and first thing in the morning I would have had a knot in my stomach. I used to hate the bus ride into the stadium, but I've got a bit better at managing that. There's still the odd game when I do get that for no particular reason.
"Sometimes I just do feel more nervous than on other days but, in general, I think I manage it a bit better.
"That doesn't mean I'm not as up for it but, personally, if I prepare well during the week and feel like I've got that preparation right, then I can be a bit more relaxed coming into the game. On the other side of that, if I don't feel like I've prepared well at the start of the week that's maybe when nervous energy starts to build.
"That's something I've learned over the last couple of years, just get my preparation done early in the week, so then I can start to build my energy on the Thursday and Friday leading into the game," explains Ryan.
Whether it be with Leinster, under Leo Cullen and Stuart Lancaster, or under the Ireland of Farrell, the importance of Ryan to both provincial and national set-ups only looks set to increase, especially with his future now secured until the summer of 2023.
Joining the ranks of the centrally contracted - a band which now also includes Ulster's Jacob Stockdale - for Ryan the process of extending his stay with his home province was an easy decision.
"It was fairly routine," he admitted.
"I was happy with how it went. I never really had any interest playing anywhere else at this point.
"There's lots more to achieve. We've had some success but it's two teams that really want to grow and are very ambitious.
"On top of that, there's great blokes and management behind both squads. I'm loving being in both set-ups at the moment.
"Stuart and Leo and Leinster and Faz here, they're always big on being yourself, having a point of view and coming to a meeting ready to have your point of view and ready to express yourself on something that you feel strongly about.
"There's been some good lessons for me there in terms of off-pitch stuff.
"I'm always trying to grow in that area. With someone like Johnny (Sexton) I think he drives things and he expects perfection which is great. I think we can all learn plenty from him."
There were plenty of lessons to be learned last week too it seemed. Scotland came into the Aviva unfancied but won the first few collisions and went from there, providing a more physical effort than we've seen from them in recent seasons. If that was unexpected Wales, in contrast, Ryan says are to be a "different animal".
"I think it went reasonably well," he reflected of the opening round win.
"In saying that there's lots of things we could have done better, there definitely is, but I think the way we defended at the end obviously, but also before half-time we had them kind of on the ropes before they got that intercept but I thought we scrambled really well there.
"I think we showed passages of real toughness as a team to defend our line like we did. But, ultimately, we need to be a bit more accurate and I think when we do get those chances in their 22, we might have got away with it last week, but I don't think we'll get away with it this week. I think Wales are a different animal.
"They've won 11 of the last 12 (competitive) matches they've played, World Cup semi-finalists, Grand Slam champions, they're a serious team.
"So we're definitely going to have to crank it up a bit."