John Kirwan's Blues have been the revelation of the early Super Rugby season, but they will face a serious test of their credentials against triple champions the Bulls this weekend.
The Blues, under former Italy and Japan coach Kirwan, have caught the eye with opening wins over the Hurricanes and Crusaders - their first back-to-back victories in a Super Rugby season since 2008.
But the unbeaten Blues now come up against their first South African opposition in Sunday's home game against the Bulls, who are embarking on a swing of four away games.
The match in Auckland will be a highlight of a weekend also featuring the table-topping Brumbies against arch-rivals the Waratahs, and the Chiefs, the reigning champions, away against the Stormers.
"This will be a very different game of football from the two games we have played against the New Zealand sides," said All Blacks great Kirwan.
"We have a similar philosophy where we all want to play exciting footy and put a lot of running into our play, but this match will be a really tough and different kind of game I'm sure."
The Bulls come into their first tour game of the campaign boosted by wins over the Stormers and Australia's Western Force, but they have yet to beat the Blues in New Zealand.
"We have four very tough games but the Blues are certainly on a high," said veteran Bulls winger Akona Ndungane.
"They beat the Crusaders last week convincingly so we know that it won't be easy. But this is the time we need to stick to our game plan and be sharp on defence. I'm sure if we pitch up on the day we can get a win there."
Blues know what's coming
And former winger Kirwan said his new Auckland team knows what to expect from the Bulls on Saturday.
"The Bulls are big on forward-orientated rugby with (fly-half) Morne Steyn getting them down there," he said.
"They try and play a bit more footy than they used to but when you have the accuracy of Steyn and the drive of Pierre Spies, you have a confident rugby team who know how to strangle football teams."
Meanwhile, the Brumbies will chase their third straight win in Saturday's grudge match against the Waratahs after going top of the Australian conference and the overall table with wins over the Queensland Reds and Melbourne Rebels.
The Brumbies, created in 1996 mostly from players regarded as rejects from NSW and Queensland, won the title in 2001 and 2004, but they hold a deep resentment towards the better-resourced Waratahs.
"We spoke about it, saying how excited we were for this week to come because it was going to be an important week," Brumbies skipper Ben Mowen said. "In terms of the importance, Waratah games are absolutely everything."
The Brumbies, under former World Cup-winning Springbok coach Jake White, are likely to give 110-Test veteran George Smith a run against the Waratahs after his return from club rugby in Japan.
In Melbourne on Friday, fly-half Quade Cooper will line up against his Australia team-mate James O'Connor when the Reds tackle the Rebels and look to make it three wins from four games this season.
Elsewhere, the Hurricanes face the Crusaders in Wellington and the Highlanders host South Africa's Cheetahs in Dunedin.
Elsewhere, reigning champions the Chiefs are away to the Stormers in Cape Town and newcomers the Southern Kings have home advantage against fellow South Africans the Sharks in Port Elizabeth.