The champion Crusaders remain the side to beat, despite a long-awaited resurgence from the Blues.
That's the verdict from World Cup winning coach Sir Graham Henry, who led the Blues to their first two titles and had a big hand in their third.
Henry implied he had some doubts about the Crusaders attacking creativity, but still rates them as this country's best side.
He was hugely impressed with the Blues' defence in their opening Super Rugby Aotearoa games against the Highlanders and Chiefs, although he said the Highlanders' flat attack exposed them in the latest round.
Confidence and spirit were central to the Blues' run of seven wins, and he praised the captaincy of Patrick Tuipulotu, the coaching/selecting, and the influence of rugby superstars Beauden Barrett and Dan Carter.
"Still, I think they've (Blues) got a big hurdle," he told Newstalk ZB's Martin Devlin.
"The Crusaders are the number one team in the country from the three rounds we've seen so far.
"But they are not unbeatable. The Blues will play to the peak of their ability (against the Crusaders) - whether that is good enough who knows?
"The Crusaders score most of their tries from opportunities, they switch on to opportunities.
"They scored two against the Chiefs, one a quick throw in at a lineout which was a bit questionable, and another from a high ball that was bobbled by Damian McKenzie.
"They collected that and scored in the corner. They scored two opportunist tries. They often score tries from the opposition's mistakes.
"But the Crusaders will bring out the best in them (the Blues)."
Henry believed that captain Tuipulotu had "got his feet under the table" and his self-confidence was flowing through the team.
"Beauden Barrett has made a difference to the confidence and intellectual property of the group," he said.
"Even Daniel Carter – I know he hasn't played yet - but just his presence and being on the sideline as water boy. That will give a lot of the guys confidence to play the game.
"They are playing with world class players with a very good understanding of the game, and that transfers to the rest of them.
"They don't want to let them down, they've got respect for those sort of people. That lifts the rest.
"They've come of age a wee bit, been together for a while. The selectors and coaches have been consistent.
"(Blues coach) Leon MacDonald has done a great job and has great people around him. They've shown some real backbone (on defence) which shows there is a good culture in the team."
Henry was also impressed with the young halves Sam Nock and Otere Black. Halfback Nock was a junior star who begun to find his feet. Black was playing "outstandingly".
"They won ugly against the Highlanders, but that's what good teams do," he said.
"A year or two ago they wouldn't have won that game."
Meanwhile Henry said the buzz around the game showed what "scarcity" can do, and he predicted a full house at Eden Park for the final round clash between the Blues and Crusaders. He is also a big fan of afternoon games.
And the referees and rule interpretations were playing their part.
"They are tidying up the interpretation of the tackle, making sure players are not falling over the ball and coming in at the side," he said.
"The offside line has been a pain in the arse for a long time.
"There are also very few high tackles now. Players get used to it (changes), refs are getting better at it."