Maybe it was because they played in white jerseys and resented the fact that the opposition were allowed to wear blue. Maybe the dinosaur jibes had finally struck home, and maybe the Waratahs are a directionless rabble, unrecognisable from the contenders of the last two seasons.
Whatever the reason, we have to acknowledge the most comprehensive display by a South African side in Australia in the long and painful history of Super Rugby. Last Saturday, the Bulls scored four tries and climbed to third position on the log, recording their first-ever win in Sydney.
How did they achieve this? Well, their forwards dominated the tight phases, Victor Matfield gave his familiar master-class in poaching opposition line-outs, Bryan Habana out-sprinted everybody and Fourie du Preez gave a textbook display of how to play scrumhalf in the modern game.
But those things happen every week the Bulls play, so what went right? Why did the same virtues not presage the familiar Antipodean implosion, leading to a comprehensive defeat after a promising opening? Could it be zeitgeist?
After all, here we are, less than halfway through the tournament and the Lions, Bulls and Stormers have recorded more wins away from our shores than our franchises normally manage in two seasons.
But if it were zeitgeist, would the Bulls have needed to travel halfway around the world from fortress Loftus to show their true mettle?
What happened to the team that collapsed against the Force and failed to engage either brain or second gear against the Sharks in Durban? What happened to the lazy, disinterested Habana who looked a pale mockery of the player who has scored a try for every Test he’s played?
Imagine how Australia’s teams are soaking this up. In the worst year, they could always guarantee wins against the Lions, the Bulls and the Springboks.
Now they have no guarantees and their rugby league converts are queuing up to return to the 13-a-side code.
It may be early to be talking about home semifinals, but it is not too early to predict that there will be no Australian team in the last four. Their teams have been shorn through injury of key players like Stephen Larkham, Chris Latham, Phil Waugh and Dan Vickerman.
Things are rather different in this country, where a talent as dynamic as JP Pietersen may have to learn about life in the Vodacom Cup, so profligate has the Sharks wing become with possession. Against the Cheetahs last week the 20-year-old dropped everything that came his way until he hung on to the intercept that decided the match in Bloemfontein.
Pietersen also scored two tries against the Bulls at the commencement of the campaign in Durban, yet it was impossible to declare that he had had a good match. Perhaps the kindest thing that can be said is that he is the sort of player to whom things happen; others are not quick or intuitive enough to be in the right place to make a mistake in the first place.
Nonetheless, Dick Muir’s side oozes talent and Pietersen needs to learn sooner rather than later that there is no room for underachievers in a team that has serious designs on the title.
No South African side has ever begun a campaign with five successive wins, so it is only natural for people to go over the top about what the Sharks have already achieved.
They have two more home games before travelling overseas and just two more wins from the next eight games plus a couple of bonus points should ensure a semifinal berth.
That is defeatist talk, of course, for as the only unbeaten side in the tournament, the Sharks should be looking for a home semifinal and, naturally, a home final.
Such has been the level of underachievement by our sides in Super Rugby that such talk is taboo, an unwanted display of hubris.
Yet the fact is that Muir’s men have recorded five wins while never getting out of third gear. One day soon everything will click and they’ll butcher some poor team.