New Zealand's dominance of Super Rugby Pacific will continue for another year after the Blues snuffed out the hopes of the remaining Australian side, beating the Brumbies 20-19 at Eden Park.
A brave second-half fightback saw the Brumbies fly home from a 20-7 deficit with two rolling-maul tries for substitute hooker Lachie Lonergan, only for Noah Lolesio's drop-goal attempt in the dying seconds to be charged down by Blue Ofa Tu'ungafasi.
It clears the path for the Blues to host the Crusaders in the final next weekend, and left Brumbies' skipper Allan Alaalatoa heartbroken.
"We showed a lot of heart there during the second half, gave ourselves an opportunity to win that game, but didn't quite ice it at the end ... I'm just pretty disappointed at the moment," he told Stan Sports.
"The spirit in our team is huge, we knew it was going to take a hell of an effort for us to come out here and get the job done.
"We spoke about collisions, set-piece ... our set-piece really brought us home there in the second half. The boys showed a lot of heart especially there in the last five or so minutes."
It looked good early for the Brumbies when centre Irae Simone scored inside three minutes, but the Blues reeled off 20 straight points to claim control with Hoskins Sotutu and Mark Talea crossing for tries.
But the comeback began when Blues' hooker Kurt Eklund was sin-binned for a dumping tackle on Andy Muirhead, although in-form flyhalf Beauden Barrett was once again on hand to deliver a try-saving tackle in the corner on Tom Banks.
The Brumbies finally broke the line through via Lonergan at the maul, but Lolesio's unsuccessful conversion attempt came back to haunt the visitors.
Lonergan barged over for a second try on 77 minutes and Lolesio did slot that conversion to cut the lead to a point.
But he couldn't seal the deal with the subsequent drop-goal attempt.
Barrett was easily the best player on the field, constantly creating opportunities for the Blues while flawless in defence and running for 99m.
"I've got a lot of trust in the lads, we've got to give it to (the Brumbies), they could have easily run away with that one," Barrett told Stan Sports.
"We knew we had to fight hard and work hard together to close that out.
"Those sort of moments (Tu'ungafasi's chargedown) you've just got to be alive for and look for ... his edge is exceptional and we needed the big fella to stand up in that moment."
While the Blues were dominant in most areas, they were brutal at the scrum and their pack forced four penalties.
They struggled with discipline in the second half, conceding eight penalties to four and they were perhaps lucky not to receive a yellow card for the repeated infringements.