For our money, there isn't another rivalry like it in Irish female sport. Handballers Martina McMahon and Catriona Casey met in two All-Ireland finals last year, both of which came down to 21-20 third-game wins for McMahon, the closest possible result there is.
To put that in perspective, there has only been one other 21-20 third game result in a Senior Singles All-Ireland final this century, in men's and women's handball. For two to occur in the same year, between the same players, is extraordinary.
Then again, this is an extraordinary time in the sport, with two amazing ladies players in their prime and going head-to-head in most major finals.
Cork's Casey held the upper hand, no pun intended, for a couple of years after her Limerick counterpart arrived in senior ranks but the last 18 months has been all about McMahon, who also defeated Casey in the final of the World Championships last August and, recently, in the Irish Open.
Not that McMahon is resting on her laurels.
"I suppose on paper I am number in the world but to me I still have a lot of work to do," she said last week.
I know there are going to be players chasing my tail but I am just aiming to work on my own game and stay focused on what I want to do for myself and my own goals. To put it bluntly, I am not bothered, you could say, with ones coming chasing me, I am just focused on myself and what I want to do and hopefully it all goes to plan.
At the pre-championship launch event in Croke Park recently, onlookers commented on the slight tension between the duo. There's a high level of mutual respect there but the familiarity of facing off in major finals so often has left a degree of distance between the Munster rivals.
What makes this rivalry most compelling are the contrasts in their respective styles of play. Casey, a schoolteacher, is methodical in her approach, rarely making hand errors and clinical in the front court.
Former Limerick camóg McMahon is more explosive, favouring a high risk attacking style.
Casey wouldn't be drawn on McMahon - who she is likely to meet in the O'Neill's All-Ireland final later this month again should both progress - at the launch day.
“I'd love to have something different to say but to be honest I just concentrate on my own game", she said.
“I'm enjoying my training as much if not more than ever. I feel like I'm making progress, hopefully the changes I've been making will translate in competition when the pressure is on. Look, the rivalry is good, it's keeps us all focused and working hard.”
Defeat in the Worlds in particular hit the Ballydesmond woman hard. On returning from Minneapolis, she took up employment in Dublin and immediately set about fixing some weaknesses in her game.
Casey threw herself into the handball circuit in the capital and became the talk of ball alleys around the country when she entered, and advanced to the final of, the men's Senior Singles in the Dublin county championships, an unprecedented feat for a female.
“You don't ever get over it,” she says of losing the World Championships final.
But I'm quite a persistent person, I will just keep coming back. I hate handball for a couple of days after I lose a game but I can't stay away.
Word from sparring partners has it that Casey has been more aggressive in her approach of late; where once she looked to quench McMahon's fire with icy defence, she is now preparing for what, against McMahon, seems an inevitable attacking shoot-out.
In the final of Irish Open - the biggest tournament outside of the All-Irelands - recently, Casey led 13-5 in the first game (to 15) but McMahon blitzed her with all-out offense to claw it back and win.
Her strategy is simple - shoot the ball, early, often and as low as possible.
"I would be pretty laid-back alright, nothing really fazes me, as you could see from the Irish Open final. I was losing well in the first game but I just went all guns blazing really. I have a one-track mind, if there's a killshot on, that's what I am going for.
McMahon, though, insists that her thoughts are not dominated by her Cork rival.
No, I wouldn't be focusing on that, there is a lot of hype around the place about it and there are a lot of people that want insights into my thinking about it and it's probably the same Catriona.You could get caught up in all of that but that's not for me, I just focus on what I want to do, just focus on myself and not get into any mind games like that.
The quarter-finals in the O'Neill's Men's and Ladies' Senior Singles championships serve off this Saturday, with Casey meeting Rebel colleague Aishling O'Keeffe and McMahon taking on promising Kildare teenager Leah Doyle.
In the Men's Senior Singles, the tie of the round is the meeting of number one seed Diarmaid Nash from Clare and veteran former winner Eoin Kennedy of Dublin.
Also down for decision are Martin Mulkerrins, the champion, against Wexford's Gavin Buggy and Kilkenny brothers Peter and Patrick Funchion who face Robbie McCarthy and Charly Shanks respectively.