Joe Pietersen missed an extra-time conversion to hand the Brumbies a 19-17 win over the Stormers in a disappointing Super 14 clash at Newlands on Friday.
The game looked to be heading for a draw when Brumbies flank George Smith scored an intercept try with two minutes left to play.
Pieter Louw replied however in the final minute leaving Pietersen - who had otherwise had an excellent game - with a potentially game-leveling conversion, which he sent wide of the uprights.
It could not have been a more evenly-contested clash. Before Smith's try neither side was ever ahead by more than three points.
It took over 77 minutes to see the first try, as the Stormers handling let them down at vital times while the Brumbies played a cagey game of rugby on the road.
The Stormers had two early opportunities to open the scores. Twice they chose to kick the for touch rather than take the points and both times they were unable to capitalise.
On the first occasion they made a hash of the line-out and on the second the TMO reckoned the ball had just grazed the touchline when Pieter Louw stretched out an arm at the back of a rolling maul.
Joe Pietersen finally did get the scoreboard moving after a quarter-of-an-hour with an easy penalty...but three points were scant reward for the home side's early domination.
It didn't take long for the Brumbies to reply with Matt Giteau bisecting the posts to level the scores.
Another near-chance for the Stormers went a begging after Juan De Jongh broke clear, but Pietersen found the mark again to restore the slender lead.
The Brumbies were varying their game excellently when in possession and Giteau duly squared the scores after half-an-hour at 6-all.
And that's how the half ended as the Brumbies gained in momentum and confidence.
As expected the tempo was stepped up in the second period and the hosts were first to draw blood when Pietersen slotted his third penalty.
Like clockwork, the Brumbies replied in kind and once again it was even-Stevens with 30 minutes left to play.
Entering the final quarter the visitors took the lead for the first time when Giteau found the mark with his fourth penalty - only for Pietersen to do the same a few minutes later.
The scoreboard read 12-12 with three minutes to go when Brok Harris threw a loose pass in the edge of his own 22.
You don't need to give George Smith more than half a chance, and the Test veteran run in untouched after plucking the ball out the air.
Newlands fell into a deathly silence only to erupt minutes later when Louw ghosted over off the back of a maul form an attacking line-out.
Cape Town held it's breath as Pietersen lined up his conversion. The score line tells the rest of the tale.
Man of the match: We had already decided to give this award to George Smith before he scored that vital try. The Brumbies flank was tireless in getting around the pitch and was a key attacking weapon for the tourists.
For the Stormers:
Try: P. Louw
Pens: Pietersen 4
For the Brumbies:
Try: G. Smith
Pens: Giteau 4
Stormers: 15 Joe Pietersen, 14 Gio Aplon, 13 Jaque Fourie, 12 Juan De Jongh, 11 Bryan Habana, 10 Peter Grant, 9 Ricky Januarie, 8 Duane Vermeulen, 7 Francois Louw, 6 Pieter Louw, 5 Andries Bekker (c), 4 De Kock Steenkamp, 3 Brok Harris, 2 Tiaan Liebenberg, 1 JC Kritzinger.
Replacements: 16 Deon Fourie, 17 Eusebio Guinazu, 18 Anton Van Zyl, 19 Pieter Myburgh, 20 Dewaldt Duvenage, 21 Lionel Cronje, 22 Sireli Naqelevuki.
Brumbies: 15 Adam Ashley-Cooper, 14 Pat McCabe, 13 Stirling Mortlock, 12 Christian Lealiifano, 11 Francis Fainifo, 10 Matt Giteau, 9 Josh Valentine, 8 Stephen Hoiles, 7 George Smith, 6 Rocky Elsom, 5 Mark Chisholm, 4 Ben Hand, 3 Salesi Maafu, 2 Stephen Moore, 1 Ben Alexander.
Replacements: 16 Huia Edmonds, 17 Guy Shepherdson, 18 Justin Harrison, 19 Mitchell Chapman, 20 Patrick Phibbs, 21 Matt Toomua, 22 Tyrone Smith.
Referee: Craig Joubert