The Brumbies will have home advantage in the Super Rugby AU final next month after sealing top spot with a 31-14 defeat of Western Force on Friday.
Dan McKellar's side will finish the regular season at the summit a week on Saturday following a victory over the bottom side at GIO Stadium.
Fergus Lee-Warner's try, converted by Ian Prior, gave the Force a surprise early lead but the Brumbies held a 10-7 half-time advantage courtesy of five-pointers from Tom Wright and Thomas Banks
The leaders also had two tries disallowed in as many minutes in the first half, but Will Miller was not to be denied when he crossed 11 minutes into the second half as the Force came under immense pressure.
Jono Lance touched down at the other end, with Prior successfully converting again to reduce the deficit to three points, but academy graduate Len Ikitau's first try for the Brumbies and Andy Muirhead's late effort finished the Force off.
Bayley Kuenzle was on target three times from the tee in a sixth win out of seven for the Brumbies.
McKellar might opt to ring the changes against the Reds next week ahead of a showdown for the title on September 19, while the Force remain winless.