Belief, real belief, the deeply held conviction that you can defeat the opposition is an essential ingredient, any day you take the field in the championship. It's an intangible. It's not something you can buy or measure. But failing to acquire it effectively dooms you to failure.
Of the four sides that feature today, it goes without saying the Kilkenny players have it. The Limerick and Tipperary players will all take the field with it as well this afternoon. That leaves Wexford. The biggest challenge facing Liam Dunne since his side were pitted in the same half of the Leinster draw as Kilkenny will have been convincing his players that this is a game they can win.
I still recall vividly the image of Brian Cody falling to his knees in despair behind the Canal End goal in Croke Park in June 2004, as Michael Jacob was about to billow the net to secure a famous last-minute smash and grab Wexford victory. Powerless to do anything about it, the Kilkenny manager could see it unfolding, almost in slow motion, yards from where he stood. I wouldn't imagine it's something he's forgotten.
Wexford haven't defeated Kilkenny since. In the meantime, several punishment beatings have been administered, and a generation of Wexford players had any ounce of belief that they could repeat that famous victory, systematically eliminated in the process.
If the players Dunne is working with are carrying those scars, turning it around would be nigh-on impossible. But this is essentially a new Wexford team, many of whom have never tasted senior championship defeat to Kilkenny. That has surely made the job easier. Kilkenny's less than stellar league campaign, the retirement of so many household names and the injury to Richie Power are all added bonuses for the Wexford manager, because they all chip away at the aura of invincibility that this Kilkenny side have had for so long.
So, while there's probably never a good time to have to play Kilkenny in the championship, especially in Nowlan Park, this from a Wexford perspective may be as good a time as any.
The argument that Kilkenny have only lost JJ Delaney to retirement from the 15 who started last September's All-Ireland final replay is valid. But what a loss he is, and in such a pivotal position. Finding his replacement would have been priority number one for Brian Cody during the spring.
I spoke to a number of former Kilkenny players at the league semi-final in Nowlan Park a few weeks back, and a couple of them felt Cody would persist with Paul Murphy in the position for the championship. That was something I wasn't so sure about. Not only had Murphy struggled, particularly against Clare, but a by-product of him in the number three shirt was they were losing the lockdown qualities he gave them as arguably the best corner-back in the game. Restoring him to his natural position makes sense.
Joey Holden is the man tasked with filling Delaney's boots this summer, and if anyone can coach him up to the level required, it's Cody. Holden (pictured) could probably do without the added responsibility of the captaincy, but he has pace, the right attitude and a defensive structure around him that will surely be designed to offer the maximum protection. Given the stellar cast of full-forwards he may yet have to contain over the summer - Joe Canning, Seamus Callanan, Shane Dowling, Shane O'Donnell, and starting today, Wexford's Conor McDonald - Kilkenny's year could well hinge on how he copes in the position.
If Delaney is a big loss at one end, the news that Power's knee injury seems to be taking time to come right is an equally big one at the other. Kilkenny would not have won the All-Ireland last year without Power, and with question marks over Michael Fennelly's fitness in the build-up to today's game, they can ill afford injuries to any of their other key players.
The most heartening development for Kilkenny last year was probably the manner in which Richie Hogan, TJ Reid, Colin Fennelly, Cillian Buckley and the other 20-somethings stepped up into the leadership roles vacated by the likes of Henry Shefflin, Brian Hogan and Tommy Walsh.
Nonetheless, on the training field and in the dressing room, these veterans would still have exerted a big influence. The fact they're now gone will leave a vacuum. Admittedly a vacuum no county is better equipped to fill, but it's a big ask for the next wave to bring the same level of drive, leadership and refusal to bend as their predecessors.
If Wexford are to have a realistic chance, containing Reid and Richie Hogan should be their starting point. That's easier said than done, especially in the case of Hogan, who is liable to pop up anywhere. But because of the influence he's capable of exerting, and the scoring threat he represents, man-marking him is something Wexford should be giving consideration to. Eoin Larkin's form hasn't been great, both Walter Walsh and Colin Fennelly can be inconsistent on the scoring front, so minimising Reid and Hogan's returns might at least make the total they have to chase attainable.
To that end, feeding McDonald is paramount. He was fantastic for them last year, but in the All-Ireland quarter-final defeat to Limerick, there were long periods when he was starved of the ball. Criminally, that was primarily attributable to bad decision-making out the field. Wexford players sent a plethora of hit-and-hope efforts wide, many of which were due to either bad shot execution or players simply taking the wrong option.
There were other days too - the Leinster semi-final defeat to Dublin comes to mind - when the wide count was well into double figures, and that makes it very hard to beat the better, more efficient sides.
Wexford have good players in their inside line, but they need to get the ball into them today, to ask the questions of Holden and Jackie Tyrrell in the Kilkenny full-back line. They'll probably need at least a couple of goals, but if their decision-making has improved from last year, they keep the wides count in single digits (15 last time out against Westmeath), start well and don't let Kilkenny get away from them, you'd be entitled to feel they have a chance.
Everything in their preparations will have been geared towards being ready for today, a big Wexford crowd will travel and they showed last year, against both Clare and Waterford, that they are capable of delivering a big performance.
However, there are too many ifs, and they could have done without the controversy last week surrounding Jack Guiney. It's a big ask, especially in Nowlan Park, and I'm not convinced that they have enough overall quality just yet to be able to pull off the win.
Switching to Munster, there are few more intimidating places to get a result than the Gaelic Grounds in Limerick. I never liked playing there, especially when the home side were at their abrasive, physical best and the home crowd were getting behind them. When the decibel levels in the ground rose, the Limerick players seemed to feed off it, and we paid the price in 1996 in particular for not putting them away when we had the chance. Two years ago, when they ratcheted up the intensity levels in the second half, and the big hits were going in, the crowd never left their feet, and Tipperary simply had no answer to it.
TJ Ryan and Dave Clarke understand the importance of that. Unless Limerick are playing with that fire, passion and intensity, they're at nothing. It's the essence of who they are; and when they marry it with the cool heads and decision-making on the field that enabled them to catch Tipperary on the line last year, they make formidable opponents.
If Tipp weren't prepared - physically or mentally - for the intensity Limerick brought two years ago, they surely will be today. This is a massive game for them. They haven't won a match in the Munster championship since Eamon O'Shea took the helm, and that's not good enough for this bunch of players. Another trip through the qualifiers, with the uncertainty that brings, is the last thing this side needs, not to mention the damage it would do to their confidence in the process.
But if they are to win, they are going to have to do it the hard way. Limerick will do everything they can to deny Tipp the space their forwards crave, and make it every bit as physical as it was in 2013. The team they have picked, with David Breen back in the side, and plenty of proven ball-winners in the middle third, reflects that. Tipperary still have to prove, to themselves as much as anyone else, that they are capable of going to war and winning that kind of match.
I think they are. I thought the same last year, and the year before for that matter, and was proved wrong on both occasions. But the stakes are higher now for this bunch of players, and I think we'll see that reflected in their performance.
That said, Limerick have every right to be confident. The reports are they have trained well since the Clare match; in Cian Lynch they have one of the best young players in the country; and Tipp are without Noel McGrath and Cathal Barrett.
However, I have my doubts about the Limerick defence and their full-back line in particular. The fact that 'Bubbles' O'Dwyer has been passed fit is a huge boost to Tipperary, and in a game likely to be decided by small margins, having him on the field could be enough to tip the scales their way.
Sunday Indo Sport
Tipperary and Limerick is the fiercest rivalry of them all. I hadn't realised just how bad it was until I went to match with a friend from a part of Limerick so close to Tipperary the apples fall off the trees from one county into the other. This normally mild- mannered man went off the head.