His team united a nation on St. Patrick's Day, but coach Joe Schmidt says the age divide within his Ireland squad helped secure this year's Six Nations championship.
Of the starting lineup that defeated England 15-24 at Twickenham on Saturday, seven had made fewer than 25 appearances for their country, and four of those fewer than 10. At the other end of the spectrum, six players boast more than 50 caps.
Ireland secured first Grand Slam since 2009
Coach Schmidt hails mix of youth and experience
Captain Best say side will be 'hungry' for more
"Youthful enthusiasm is being tempered by the experienced guys that certainly have been there before," said Schmidt. "That blend is working quite well for us at the moment."
Ireland's players were crowned champions in the swirling London snow, claiming their country's only third ever Grand Slam and first since 2009, in the process condemning England to its worst finish in the competition in 35 years.
Of the emerging stars of this Ireland team, Schmidt singled out winger Jacob Stockdale, who, with seven tries in this year's tournament, set a Six Nations record. Easy to forget that he's 21 -- "still a kid," in his coach's words.
"He's played every game, and he's done incredibly well and he's growing and learning," said Schmidt. "People take for granted that he hasn't played much rugby at this level, or even provincial level for that matter."
Around Stockdale was also a backline rich in experience -- the likes of Keith Earls on the opposite wing and Rob Kearney at full-back; the whole tournament could have taken a different narrative had Johnny Sexton not struck a wonderful, last-gasp drop goal in Paris on the first weekend.
The Grand Slam inevitably sees heads turn to next year's World Cup as Ireland climbs to second in the world rankings for the first time since 2015.
"It all depends on how we kick on," said captain Rory Best, who also starred in Ireland's 2009 Grand Slam.
"When you look especially at the younger players -- the way they've come in and not just fitted in but they want to just keep getting better. As long as they keep that mentality, the guys that are slightly older, if they keep that want to keep going forward that's all you can ask.
"We'll always want more because we're competitive and maybe a little bit greedy."
Schmidt jokes that Best, at the age of 35 and with 111 caps to his name, is "getting faster and faster on that Zimmer frame."
"We'll see how we go with that," he responds, when asked if the Ulsterman could lead Ireland into next year's World Cup.
England left soul-searching
Questions over Japan 2019 are happy ones for Irish fans; for England, which has lost three in a row for the first time since 2014, the post mortem is more testing after they finished fifth, just above Italy.
England coach Eddie Jones, who had seen his side lose just once prior to this year's Six Nations, was keen to draw positives from a campaign which saw losses to Scotland and France as well as Ireland.
"Every team that I've had that's been a champion team has had a run like this," he said. "It's just about being instrumental in how you remake yourself.
"We've had to develop the internal part of the team, how our coaching staff and players work together, how our team must take more responsibility for the game ... We've made some really good development in those areas.
"For us it's been an enormously beneficial if not disappointing tournament because we're finding out how to be a better team."
Jones has kept no secrets about his desire to win next year's World Cup, and that task now appears taller than it did six weeks ago.
While Ireland mastered the balance of youth and experience, England struggled to find the right combination of players in the right areas, notably in the back-row and the midfield.
"Some guys have come in and done really well. Other guys are maybe going to struggle to participate in the future," said Jones.
"We have to get a greater depth to our squad. The depth to our squad is players who can play Test rugby."
Can a European team produce 'New Zealand performance'?
With Australia and South Africa struggling for form, Northern Hemisphere sides are likely to pose the biggest threat to New Zealand ahead of next year's World Cup.
Wales, Scotland and France, who occupied the middle spots of the Six Nations table, will take plenty of positives from recent performances.
France, in particular, written off by most on the eve of the tournament, got the better of England for the first time in the Six Nations since 2014 and was inches short of beating Ireland and Wales.
Scotland's tournament came to a close with an unconvincing, last-gasp win over struggling Italy, but the victory over England at Murrayfield, its best in recent years, will live long in the memory.
"The game against England was a great performance and a great win because of what it meant for the country, but having watched it a few times I know we could have been better," said coach Gregor Townsend.
"We know a lot of work has to go in over the next 18 months. Over the next 12 months to have a better championship, and then over 18 months to have a good World Cup."
"In terms of performances in games I don't think we have produced our New Zealand performance or our Australia performance, though for 60 minutes of the England game we were right up there."