It's an on-field rivalry that may never be repeated.
And according to two of its fiercest combatants, what happens between the Brisbane Broncos and North Queensland Cowboys stays on the field.
Three of the past five matches between the sides have gone to extra-time, including their most recent encounter in week two of the finals that saw a piece of Johnathan Thurston magic get the Cowboys home in a 26-20 thriller.
In fact, that six-point margin was the biggest between the two sides since Round 10, 2015, with the four previous matches being decided by a combined seven points.
Each contest has tested the physical limits of everyone involved, with the 2015 golden-point grand final regarded by many as one of the greatest games ever played.
Given the recent successes of both teams, four Cowboys and three Broncos were selected in Australia's 24-man squad for the upcoming internationals at home and abroad, but don't expect any animosity from the players involved.
Speaking to NRL.com in Sydney's eastern suburbs, Kangaroos veteran Sam Thaiday said the off-field banter between the two Queensland clubs was one of his favourite parts of representative camps.
"It's a pretty playful environment in the sense that we give each other a fair bit of stick and we take a bit of stick back," Thaiday said.
"That's what I love about being around the boys all the time because there's that banter and healthy rivalry between us. There's no harm intended between anything that gets said and we all have a bit of a laugh and a carry on afterwards."
Thaiday said he was ready for whatever great mate Johnathan Thurston had to say on tour, and warned the Cowboys he had ammunition up his sleeve if they brought up last month's epic in Townsville.
"If they do then I'll tell them to pull their heads in and just remember the last game they played," he laughed.
"I'll probably be leading that, so JT can say whatever he wants and I'll just keep on coming with my one-liners."
Broncos teammate Matt Gillett said the closeness of their recent matches was unprecedented, and admitted he'd be more than happy for their next meeting to be a one-sided affair.
"The contests that we've had for the past two years – from last year's grand final to this year's matches – are something that you don't see too often," he told NRL.com.
"I think if you talk to guys from either team, everyone will tell you that we're a bit over all these tight games.
"That's just footy and that's how it goes sometimes. We just leave that rivalry out on the field, and once you come together in a camp like this then you're friends again.
"They don't rib us at all, but I'm sure after a few beers on tour then that might happen a bit."