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.