The Western Force heaped more Super Rugby pain on the Brumbies with a 27-19 victory in Sunday's Australian derby at Canberra Stadium.
A second-half tryscoring double from winger David Smith and a 15-point haul from playmaker James O'Connor piloted the Force to only their second win from eight starts in2011.
The Brumbies' loss, though, completed a sorry opening round of derby defeats after the two-time Super champions also lost to the Melbourne Rebels (25-24), Queensland Reds (31-25) and NSW Waratahs (29-22).
The Brumbies' one-time home-ground fortress is now proving more a gateway to four competition points for visiting teams, with the ACT franchise a dismal one from four in Canberra this campaign.
And while the Force were plucky, the Brumbies should never have lost this one.
The Brumbies led 10-7 at halftime but their advantage could have been much greater had Giteau not spurned two simple penalty goal attempts from in front of the Force posts.
On the first occasion, the Brumbies lost the ensuing lineout and then Christian Lealiifano turned over possession, allowing the Force to score a 75-metre try against the run of play through O'Connor on the stroke of halftime.
first five-eighths Will Ripia added the conversion to narrow the deficit to three points at the break.
The Brumbies had opened the scoring in the sixth minute with a Giteau penalty goal.
Giteau capitalised on a Lealiifano break to put the home side 10-0 up with a converted try in the 21st minute - but the Brumbies failed to press home their advantage.
After inviting the Force back into the contest, Giteau - twice bitten, thrice shy - had no hesitation opting for goal and landing a 44th-minute penalty to give the Brumbies a six-point buffer.
But the Force hit the lead for the first time a minute later when, after failing to secure possession from the kick-off, the Brumbies conceded a try to winger David Smith.
O'Connor's sideline conversion made it 14-13.
A third Giteau penalty restored the Brumbies' lead before O'Connor nailed a 46-metre reply to put the visitors back in front 17-16 after 63 minutes.
Giteau and O'Connor traded further penalty goals as the lead changed hands four times in the final half-hour before Smith sealed victory for the Force two minutes from time when he crossed under the sticks.
