Some of the biggest stars of the senior game have been moulded by their experience at U-21
As the Bord Gáis Energy U-21 All-Ireland Hurling Championship reaches its final stages, the quality of the games has shown once again that there is a huge amount of talent coming through the grades.
The U-21 All-Ireland Championship has proved throughout the years to be the place where some of the best players have cut their teeth, tasting success or disappointment along the way, helping to shape their talent.
Here are just a few of the stars that have come through that breeding ground over the years.
Joe Canning is still on the quest for his first All-Ireland title at senior level, but he knows what it takes to come out on top in a national championship having done so at the U-21 grade for Galway.
The Tribesman had always shown promise at minor level, where he won consecutive All-Irelands in 2004 and 2005.
Two years later and the Portumna clubman had another All-Ireland, this time at U-21 as Galway came out on top in 2007, beating Dublin 5-11 to 0-12 in the final. Canning scored 0-3 in that decider, having notched 0-7 in the semi-final victory over Cork two weeks before that.
That triumph helped pave the way for Canning's progression to the senior setup, as he went on to win the Young Hurler of the Year in 2008. He is widely recognised as one of the most gifted hurlers in the game today.
The Thurles Sarsfields clubman picked up Munster Senior Hurling medals in 2015 and 2016, most impressively with the destruction of Waterford in this year’s final.
Maher featured for Tipperary minors in 2012 and 2013, winning Munster and All-Ireland medals in 2012 at corner-back.
The 20-year-old Bord Gáis Energy Ambassador captained Tipperary in this year’s U-21 Championship, only to be beaten by Waterford in the Munster final. He’s widely regarded as one of the finest up and coming Tipperary players and will be vital to the senior team heading toward the climax of the All-Ireland hurling championship next month.
It was more than a decade ago now when Michael Fennelly led his Kilkenny U-21 side to All-Ireland glory.
Admittedly, it did take two bites at the cherry, but they got there in the end with a 1-11 to 11 point victory over Tipperary in a replay in 2006. Fennelly no doubt learned a lot from the experience and has been one of the most influential members of the team in the post-Shefflin era.
Since 2006, the 31-year-old has won six All-Ireland medals, four Leinster titles and four National Hurling Leagues. The three-time All-star has fought through injuries to his hamstrings, wrists and back to retain his spot in the team, and even into the twilight years of his inter-county career is still one of the most influential players in Kilkenny hurling.
Kilkenny’s 2003 U-21 All-Ireland winning team was one for the ages. It included players like Tommy Walsh, JJ Delaney and Aidan Fogarty, all led by captain Jackie Tyrell.
The James Stephens player would win only one underage All-Ireland, as the Kilkenny minors of 1999 lost in the All-Ireland semi-finals.
Image: INPHO/Cathal Noonan
Before Tyrell became one of the most dominant players of his generation, he captained Kilkenny to Leinster and All-Ireland glory 13 years ago.
He won his first senior All-Ireland title (as an unused sub) weeks previously, but against Galway in Semple Stadium he led the team to their eighth title at the underage grade.
Nine All-Irelands and 11 Leinster titles later, Tyrell cemented his place as one of the greatest players to ever poc a sliotar.
Browne never got his hands on the Liam McCarthy Cup, but he captained Waterford as a 19-year-old to the U-21 All-Ireland Hurling Final, when the side beat Offaly in Nowlan Park.
The three-time All-Star won two Munster titles at U-21 level in 1992 and 1994, two wins which still account for half of Waterford’s four provincial titles at that level. Only this year did the side win their fourth provincial title, after a 22-year wait.
Image: ©INPHO/Ryan Byrne
Named the Hurler of the Year in 1998, Browne won three All-Stars in three separate positions (midfield, right wing-back and left wing-back). His four Munster Senior titles never won him that elusive All-Ireland medal, but he did play in one final, when Waterford lost to Kilkenny in 2008.
He remains one of the best players to never win an All-Ireland senior medal, but some of the proudest days of his career came in the U-21 set-up.
While Rushe has yet to taste All-Ireland success at senior level, he was a key part of a Dublin set-up that finally managed to produce success in Leinster and on the national stage, a massive achievement for a province where football had been seen as more or less the only game going for decades.
Coming through in 2010, Rushe was a key part of the team that claimed a provincial title, beating Wexford in the final. The following year, they replicated that success in Leinster again as Rushe was named the Man of the Match for his performance in another win over Wexford. As captain, he lead his team out in the All-Ireland final against Galway.
Although they were beaten by an incredibly strong side that year, the success Rushe had at the younger age grade set him up to enter the senior side, where he has continued to show the talents and the skills which made him a leader there. It came as little surprise then that he was named as the captain of the Dublin side for the 2016 season by manager Ger Cunningham.
Kelly's talent was spotted at an extremely early age, entering the minor set up at just 15 years of age. There, he made a huge switch in his game, moving from goalkeeper into full forward, and he never looked back.
He moved to the U-21 set-up, becoming a strong influence on the team, but thanks to the sheer talent of an outstanding young Limerick side in the early 2000s, he had to wait for his chance to taste All-Ireland glory at senior level. Still, he helped his side to claim two Munster titles in his time at that grade.
That success saw Kelly named the Young Hurler of the Year in both 2000 and 2001; as he eventually went on to captain his county.
Clare's All-Ireland win in 2013 was not a bolt from the blue - the foundations of that success had been laid by the brilliance of their U-21 sides.
Kelly was a huge part of that, helping Clare claim Munster glory in 2012, and overcoming Kilkenny in the All-Ireland Hurling Championship final that same year. A superb second half display saw the Banner lift the trophy for just the second time in their history, as they came back from going in a goal down at half-time.
Image: ©INPHO/Donall Farmer
In 2013 they were still a force to be reckoned with and came out on top to retain their U-21 crown. Kelly also made an appearance in the senior All-Ireland final as they beat Cork in a replay, two superb games that are regarded as exhibitions of hurling at its absolute finest.
Still a fixture for Clare today, he helped them win the National Hurling League this year, racking up an individual tally of 1-06 in the final with a dominant performance.
This weekend, there's a chance for some of the stars of the U-21 game to stake a claim for their inclusion in this list in years to come, as a huge double-header kicks off in Semple Stadium.
The Bord Gáis Energy U-21 Hurling Championship semi-finals see Antrim face Waterford and Dublin take on Galway, in what will be two fantastic displays of hurling, with live updates on Off the Ball and @NewstalkSport on Twitter from 4pm.