A clinical second-half performance has seen the Blues top the Brumbies 38-10 and claim a critical bonus point at Eden Park.
After the Hurricanes grabbed their third straight bonus-point victory on Friday to move to the top of the table, the Blues needed one of their own to move back to the summit of the ladder.
The first half was a tight affair, but the Blues piled on the points after the break as they ran in three second-half tries to claim a crucial bonus point which sees them top the table with two games to play.
After notching 98 points in the opening two rounds, Leon MacDonald’s put away Super Rugby AU runnersup the Brumbies with a five try to one victory to see the New Zealand sides extend their dominance over Australian teams to a perfect 13-0.
A third straight bonus-point victory taks the Blues to a perfect 15 points just ahead of the Hurricanes on points difference, with Crusaders just a point behind.
The Blues and the 'Canes have put themselves into the box seat for a grand final spot, with two bonus-point victories in the final two rounds enough to make the decider.
After a tight opening, the Blues opened the scoring when Kurt Eklund finished off a perfect lineout maul in the 17th minute.
The momentum swung in the Brumbies favour as their set-piece started to dominate. They got their reward when hooker Connal McInerney finished off a trademark Brumbies lineout maul to put the visitors in front five minutes before the break.
The Blues finished the half in style when Otere Black levelled the scores with a penalty goal before Finlay Christie put them in front with a stunning try.
Just a minute before the break, Rieko Ioane burst downfield before finding Christie who showed tremendous footwork to beat four defenders to score a spectacular try to see the Blues take a 17-10 at the break.
The home side stormed out in the second half when In-form wing Bryce Heem ran onto a perfect tip-on pass from Black to open up a 14-point lead and grab his fourth try of the season.
The home side grabbed the crucial bonus-point try after a long passage of attack that saw AJ Lam run onto a nice wrap-around line and onto another perfect short ball from Black to extend the Blues ascendancy.
The Brumbies second half went from bad to worse when replacement hooker Folau Fainga'a was sent to the sin bin for repeated infringements.
The Blues made the visitors pay when TJ Faiane grabbed the Blues fifth try of the evening, running onto a brilliant offload from Harry Plummer to round out the scoring.
Next up for the Blues, will see them cross the ditch to take on the Super Rugby AU champions the Reds in Brisbane on Friday night.
Blues 38 (Eklund, Christie, Heem, Lam, Faiane try; Black 4 conversions, penalty goal, Plummer conversion) bt Brumbies 10 (McInerney try; Lolesio conversion, penalty goal)