A 78th minute try from Tevita Kuridrani saw the Brumbies book their spot in the Super Rugby final thanks to a 26-23 win over the Bulls.
In what was a tense encounter that was anyone's for the taking throughout, it was the hosts who blinked first as they allowed a late lead to slip through their fingertips.
Early on it appeared that the match would be anything but tight, with the Brumbies potentially about to unleash a blitzkrieg the likes of the one that saw the Sharks stunned in Durban earlier in the year.
The dominance began from a clever kick-off from which Akona Ndungane was given little room to clear as he collected up against the touchline - it was a tactic that would bear fruit on more than one occasion.
After a few phases of attack, Francois Hougaard infringed at the ruck and Christian Leali'ifano opened the scoring with a three-pointer.
The visitors extended their lead at the end of the first quarter after great work from Henry Speight. The wing attacked the Bulls line at pace, bursting past defenders and brushing off the challenge of Bjorn Basson with a great hand-off before he off-loaded behind his back to Jesse Mogg who dived over in the corner. Leali'ifano added the extras.
Speight would soon have a taste of his own medicine though as JJ Engelbrecht rounded off a passage of patient - yet slightly scrappy - build-up as he put out the fend on Speight and crashed over for the Bulls' first points.
Steyn and Leali'ifano proceeded to exchange penalties as the two teams went into the break with the Brumbies holding a 16-11 lead.
It was the Bulls who started strongest in the second period and they were nearly rewarded for their efforts with a try from Grant Hattingh. The second rower looked set to round off a period of sustained pressure as he burst for the line, but the combination of a superb tackle from George Smith and some smart hands from Nic White saw him held up.
The Bulls would add three points nonetheless and a battle of the boots proceeded with the Bulls taking a 20-19 lead into the final quarter and with the momentum with the hosts.
The Brumbies looked to edge their way back into proceedings and their charge was led by Smith who - as he had been throughout the match - claimed some key steals and made big tackles. However, both sides had chances inside their opposition 22 that they weren't able to take advantage of.
The Bulls will feel the worst on this score as Dewald Potgieter on three occasions decided against the chance for an easy three points and instead went for the line which didn't produce points. The strategy seemed strange and was made a mockery of when Steyn then looked for a drop goal soon after.
While points weren't forthcoming the Bulls did achieve their goal of remaining in the Brumbies half and with three points on offering for the fourth time, Steyn was given instructions to kick for posts after an infringement at scrum time and he made no mistake.
The penalty was a sign of how the Bulls had fought their way back into the game, with the scrums an area of supreme dominance for the Brumbies early on, but that dominance then swung in favour of the hosts.
The Brumbies still had time to make the decisive move and they didn't disappoint.
With less than two minutes on the clock Matt Toomua broke down the near touchline before passing inside to Tevita Kuridrani who dived over to put the men from Canberra ahead once more. Leali'ifano added the extras to ensure a penalty or drop would not be enough for the Bulls to win it.
With the restart cleanly taken, the hooter sounded like sweet music to the Brumbies as Leali'ifano hammered the ball into touch and in doing so sent his side into the final.
Pen: Steyn 6
Try: Mogg, Kuridrani
Con: Leali'ifano 2
Pen: Leali'ifano 4
Bulls: 15 Zane Kirchner, 14 Akona Ndungane, 13 JJ Engelbrecht, 12 Jan Serfontein, 11 Bjorn Basson, 10 MornÃ¨ Steyn, 9 Francois Hougaard, 8 Dewald Potgieter (c), 7 Jacques Potgieter, 6 Deon Stegmann, 5 Grant Hattingh, 4 Flip van der Merwe, 3 Werner Kruger, 2 Chiliboy Ralepelle, 1 Dean Greyling.
Replacements: 16 Callie Visagie, 17 Frik Kirsten, 18 MornÃ¨ Mellett, 19 Paul Willemse, 20 Jono Ross, 21 Jano Vermaak, 22 JÃ¼rgen Visser.
Brumbies: 15 Jesse Mogg, 14 Henry Speight, 13 Tevita Kuridrani, 12 Christian Lealiifano, 11 Clyde Rathbone, 10 Matt Toomua, 9 Nic White, 8 Ben Mowen (c), 7 George Smith, 6 Peter Kimlin, 5 Sam Carter, 4 Scott Fardy, 3 Ben Alexander, 2 Stephen Moore, 1 Scott Sio.
Replacements: 16 Siliva Siliva, 17 Ruan Smith, 18 Fotu Auelua, 19 Colby Faingaa, 20 Ian Prior, 21 Andrew Smith, 22 Joe Tomane.
Referee: Craig Joubert