The Force won their second match of the season when they beat the Brumbies 19-27 in Canberra after two tries from David Smith.
The result is the Force's first win this season over an Australian team and their first on Australian soil.
Former Super Rugby Champions the Brumbies have now played eight matches and won two and lost six.
The Brumbies were leading 10-7 at half time after a try, conversion and penalty from Matt Giteau.
In the second half the lead changed hands several times as James O'Connor and Giteau exchanged penalties.
With 12 minutes left on the clock the Force took the lead at 19-20 after a penalty from O'Connor. The Force then played a territorial game keeping the Brumbies back in their half.
The Brumbies looked set to pick up a losing bonus point with two minutes left on the clock but the Force won a 5m attacking scrum and Smith burst through a tackle by Christian Lealiifano and powered over for his second try.
James O'Connor converted the try which meant that the Brumbies took nothing from the match but defeat as the difference was extended to 8 points.
For much of the first half it looked as if the Brumbies would canter away to a comfortable win as as they dominated in every department.
However, they found it hard to breach the Force defensive line, their only points coming from the boot of Matt Giteau in the opening minutes.
They had to wait until the 25th minute for their first try, with Christian Lealiifano ghosting through the Force backline and finding an unmarked Giteau in support.
The home side continued to pile on the pressure, but just before halftime and with the Brumbies deep in attack, Force centre Rory Sidey pounced on a loose ball and toed ahead.
The Brumbies looked to be getting back to cover but James O'Connor came from nowhere to outpace the defenders and close the gap to 10-7 at the break.
That quickly became 13-7 with a Giteau penalty after the restart, but the Force seized on another Brumbies mistake from the kick off and Smith crossed in the corner for his first try for the club.
O'Connor converted to give the visitors a 14-13 lead, with the momentum swingly firmly to the Force.
Giteau and O'Connor traded penalties before Giteau put the Brumbies back in front with his fourth penalty 15 minutes from time.
But O'Connor kicked his second penalty almost immediately to give the advantage back to the Force.
The game was there for the taking and the Force seized their chance when Smith loomed up on Rimia's shoulder and burst through Lealiifano's attempted tackle to score under the posts.
Final Score Brumbies 19 Force 27
Tries - M Giteau
Pen - M Giteau 4
Con - M Giteau
Tries - J O'Connor, D Smith 2
Pen - J O'Connor 2
Con - W Ripia, J O'Connor 2
Referee: Keith Brown (New Zealand)
Assistant referees: Angus Gardner (Australia), Andrew Lees (Australia)
Television match official: George Ayoub (Australia)
Brumbies : 1. Ben Alexander , 2. Anthony Hegarty , 3. Dan Palmer , 4. Ben Hand , 5. Mark Chisholm , 6. Peter Kimlin , 7. Michael Hooper , 8. Ita Vaea , 9. Josh Valentine , 10. Matt Giteau , 11. Francis Fainifo , 12. Christian Lealiifano , 13. Andrew Smith , 14. Pat McCabe , 15. Matt Toomua
Reserves:16. Elvis Levi , 17. Salesi Ma'afu , 18. Colby Faingaa , 19. Julian Salvi , 20. Patrick Phibbs , 21. Tyrone Smith , 22. Adam Ashley-Cooper
Western Force:1. Kieran Longbottom,2. Ben Whittaker,3. Tim Fairbrother,4. Sam Wykes,5. Nathan Sharpe (c),6. Richard Brown,7. Jono Jenkins,8. Ben McCalman ,9. Brett Sheehan,10. Willie Ripia,11. David Smith,12. James O'Connor,13. Rory Sidey,14. Nick Cummins,15. Pat Dellit
Reserves:16. Nathan Charles ,17. Pek Cowan,18. Tom Hockings,19. Tevita Metuisela,20. James Stannard,21. Gene Fairbanks,22. Alfie Mafi