In another twist to the play-offs permutations, the Blues saved their best performance of the season for last after beating the Brumbies 30-16 at Canberra Stadium on Saturday.
The result leaves the Brumbies sweating over the result in Brisbane where the Reds require a bonus-point win over the Waratahs to top the Australian conference and book their place in the finals.
All the Brumbies needed was a losing bonus point, but they couldn't even manage that as their trans-Tasman rivals outscored Jake White's troops three tries to one.
It has been a dismal season for the Blues, who have battled an unprecedented run of injuries and lurched from one defeat to another, but they managed to sign off 2012 with a convincing win.
It was a faultless effort from the visitors who were scintilating on attack as they carved up their opponents on countless occasions.
Blues scrum-half Piri Weepu missed an opening penalty kick in the second minute of the match, but after that it was full steam ahead for the Aucklanders who were celebrating their first try of the match when lock Liaki Moli powered over from close range. Weepu added the simple conversion.
The Blues' early domination continued and four minutes later flank Daniel Braid charged down the left touchline and barged his way through Jesse Mogg to score in the corner. That score signalled the Kiwi outfit meant business as Weepu converted from far out to give his side a handy 14-0 lead - the Brumbies yet to touch the ball.
After 20 minutes, the hosts finally made their way inside Blues territory and made it count when Zack Holmes slotted over a three-pointer to put the Brumbies on the board.
Some excellent work by Henry Speight then gave the home crowd reason to cheer after the winger danced his way through several Blues defenders for a superb solo try - converted by Holmes - that closed the gap to four points (10-14).
Another Holmes penalty three minutes later made it a one-point ball game (13-14), but the Blues had the final say in the first half following a monumental team effort that ended with wing Hadleigh Parkes over the whitewash. Once again, Weepu was on-target from far out and the Blues went into the half-time sheds 21-13 ahead.
The Brumbies opened the scoring in the second half courtesy of a Jesse Mogg penalty - his first successful kick after missing three prior to that.
But the Blues hit back with another two quickfire Weepu penalties to keep the Brumbies playing catch-up.
Pens: Holmes 2, Mogg
Try: Moli, D Braid, Parkes
Cons: Weepu 3
Pens: Weepu 2, Hobbs
Brumbies: 15 Jesse Mogg, 14 Henry Speight, 13 Andrew Smith, 12 Pat McCabe, 11 Joe Tomane, 10 Zack Holmes, 9 Nic White, 8 Ben Mowen (c), 7 Michael Hooper, 6 Peter Kimlin, 5 Sam Carter, 4 Scott Fardy, 3 Dan Palmer, 2 Stephen Moore, 1 Ben Alexander.
Replacements: 16 Anthony Hegarty, 17 Ruaidhri Murphy, 18 Leon Power, 19 Fotu Auelua, 20 Ian Prior, 21 Tevita Kuridrani, 22 Robbie Coleman.
Blues: 15 Charles Piutau, 14 Sherwin Stowers, 13 Francis Saili, 12 Ma'a Nonu, 11 Hadleigh Parkes, 10 Michael Hobbs, 9 Piri Weepu, 8 Luke Braid, 7 Daniel Braid, 6 Chris Lowrey, 5 Steven Luatua, 4 Liaki Moli, 3 Charlie Faumuina, 2 Keven Mealamu (c), 1 Tony Woodcock.
Replacements: 16 Tom McCartney, 17 Tevita Mailau, 18 Andrew Van der Heijden, 19 Peter Saili, 20 Alby Mathewson, 21 Orene Ai'i, 22 Albert Nikoro.
Referee: Jonathon White (New Zealand)