WHEN you speak of rivalries within the Irish squad, the battle between Jonathan Sexton and Ronan O'Gara always dominates, but there has been a tasty contest developing inside the No 10 jersey over the last year.
Since Conor Murray was promoted unexpectedly into the Ireland set-up last August, there has been a fascinating duel for the scrum-half slot with Eoin Reddan, the intrigue heightened by the Munster-Leinster aspect, which never fails to awaken provincial passions.
Murray made his international debut off the bench in the World Cup warm-up meeting with France in Bordeaux and has started six of his nine internationals.
Reddan was the starting nine for the seminal World Cup win over Australia but since then Ireland coach Declan Kidney has turned to Murray as his first-choice, with Reddan only taking the jersey when his Munster rival was unavailable for the Six Nations clashes with Scotland and England.
However, Reddan has just played a central role in Leinster's march to back-to-back Heineken Cup glory, comfortably coping with the hype surrounding Ulster's chief playmaker Ruan Pienaar in the final and revelling in the extra responsibility thrust upon him following injury to Isaac Boss.
And, with the clamour growing for Kidney to infuse the national side with Leinster's feel-good factor, Reddan is pushing hard for the starting berth in the first Test against the All Blacks on Saturday.
Either way, Ireland are well served at scrum-half at present and there are logical arguments in favour of both contenders ahead of Kidney's team announcement on Thursday.
Murray carries the greater physical presence and is an accomplished defender, sweeping back and around the fringes, essential against an All Blacks back-row containing the ball-carrying impetus of Kieran Read and Richie McCaw.
Furthermore, starting Murray allows Reddan to be sprung in the second half, where he has proven ability to provide essential impetus as matches enter their decisive phase.
The counter-argument starts with Reddan's extra experience, 42 caps versus Murray's nine, and encompasses his successful partnership with Sexton for Leinster, an easy familiarity that has not been as readily replicated when Murray has been paired with the St Mary's man.
Also, given the fact that Ireland are facing the world champions, there is a strong case for going full tempo with Reddan from the off, with the real prospect that the game could be beyond Kidney's men by the time he usually appears.
Such tight calls could understandably introduce a certain amount of tension between the two highly competitive players but not so, says Reddan.
First, there is a natural bond stemming from their shared Limerick background and also, much like the 'front-row union' existing as a breed apart, scrum-halves tend to join forces to get forwards to do what they want.
"Most nines get on well, genuinely," said Reddan. "You practise a lot together and the other thing about nine is that you all need the forwards talking to you, you all need the same things.
"So, when you go to the forwards and say, 'look, the rucking is not good enough' and the other nine is beside you saying, 'he's right, it's not', it gets sorted.
"So, it is important that you get on, you talk about the way the team is going and the way the team plays. It's very important when you're in and out of a team that you're on a similar wavelength. I have that with Conor."
The other significant aspect is rugby becoming a much quicker, more intense game in recent years and it is rare that a scrum-half these days plays for the full 80 minutes, making it essential to have two nines working in tandem and complementing each other.
"Absolutely," said Reddan. "There is a noticeable difference. I got the ball 91 times in 70 minutes in the Heineken Cup final. It is faster and if you are going well you are looking at 20 phases and the later (in the game) they are, the more reward you get for good ball. The demands have gone up and, for me, that is better news I think.
"Do you remember the ELVs? You basically couldn't keep the ball for more than three phases but after that, it just went right up, a whole new level.
"People have different styles and it does depend on what the coach is looking for, you're either pushing a game or pulling a game, there is no in between. Obviously, if you are coming off the bench, the aim is usually to push it."
Whatever role he fulfils on Saturday, Reddan has no doubt about the greatest individual threat to the scrum-half's and Ireland's need for quick ruck ball -- All Blacks captain McCaw.
"He can really slow the game down," said the 31-year-old. "If you are trying to push the game, he can just be in there, he can make a tackle and stand up. But you need your boys (forwards) to deal with that because at this stage he shouldn't be allowed because people are aware of him."
McCaw is but one aspect of a collective menace which threatens to overwhelm the Irish challenge over the next three weeks. Ireland's footballers are commanding attention back home while New Zealanders expect nothing short of annihilation for the visitors.
However, while accepting that this Test series is "the ultimate challenge" for Ireland, Reddan says it is up to the players to change the perception that theirs is a hopeless quest.
"Yeah, that (Euro 2012) is the way it works, isn't it? We will get the eyes back here if we win. It is so far away down here that you wouldn't want to be relying on what is going on at home anyway.
"I can't say for the lads who won the Grand Slam but I can say for my personal achievements, if we beat the All Blacks, it would be the biggest thing. It is a massive opportunity. Let's go for it."