Rivalries are hard to create in the contrived world of Super Rugby where there is little history and manufactured geographical boundaries. But the Crusaders and Bulls have managed to build a healthy disrespect for each other over the years and their rivalry has added a much-needed dose of spice to an otherwise entertaining but emotionally bland competition.
Local derbies, particularly those in New Zealand, have become intense, competitive affairs but no two sides have come to loathe each other: no one has built a genuine grudge match which is what last night's fixture in Christchurch was.
The source of their rivalry is hard to tell: ambition could be the root cause. The Crusaders are New Zealand's premier side and the Bulls have long aspired to emulate the results of the men from Christchurch.
The best from New Zealand playing the best from South Africa - tension is inevitable. Maybe there's more to it: could the fans in Pretoria and the rabid hostility experienced at Loftus Versfeld have brewed a festering dislike of the Bulls among the Crusaders? Or are the people of Christchurch more similar to the fans in Pretoria than they realise and is it their similarities that has brewed this tension?
The cause doesn't matter. The rivalry has been since Andrew Mehrtens gave the Loftus crowd the finger in 1999 after he landed a late drop goal to seal an unlikely 30-28 victory. It was unforgettably spiteful - his unbridled joy at sticking it up a crowd that had been on his case from the kick-off. The edge has been there ever since and the last five years or so have seen the intensity increase.
In 2010, the animosity lifted when the Crusaders thought they had pulled off an impossible and much-needed win in Pretoria. They had shockingly lost to the Western Force on the way to Africa and needed the points to preserve their position at the top of the table. When they charged down a last-minute drop goal while leading 35-33, they thought they had won. But somehow the Bulls kept the ball alive and scored in the corner - and there was a clear forward pass along the way.
The Crusaders were beside themselves; the nature of the defeat and the Bulls' reaction stoked the visitors' anger. The defeat cost them as it dropped them to fourth and they had to return to Pretoria for the semifinal - which they lost in another classic, if ill-tempered game.
Fires really began to burn earlier this year when the Crusaders lost an epic 32-30 match but were then accused of eye-gouging by Chiliboy Ralepelle and Flip van der Merwe. Crusaders coach Todd Blackadder said it was all rubbish designed to destabilise his team. A Sanzar investigation found no evidence of foul play.
It was no surprise, then, to hear Blackadder play down the state of the rivalry during the week.
"We've had a good relationship with the Bulls for a long time, well before my time [as coach]," he said. "Certainly, both parties weren't happy with it [eye-gouging claims] but we've had a good chat on the phone and we've put it behind us.
"They're a class side no matter where they play but it's a huge challenge travelling over there and playing against them. Their stadium is amazing and they have a very hostile crowd, which is part of the reason why they've been so successful at home."
Last night was the third time in four years these two have clashed in the play-offs and each one has been a cracker - adding to the history and building the sense of these two teams being the two on which Sanzar banks on to build and maintain interest in Super Rugby.