Jake White's team is chasing a sixth consecutive victory away from Canberra - a feat no other team has achieved in the competition's 18 years.
But with four weeks of games against South African teams, White says the Brumbies' defence is the foundation for the side's rise.
In three games this year, the Brumbies have not conceded a point in the second half.
White is the defence technician, while former NRL coach Brian Smith has helped add extra starch to the tackling and contact zones.
However, the young Brumbies will face a stern test when they take on the Sharks at Kings Park in Durban - a place where the club hasn't won since 2007.
''We use defence to strangle teams and turn the ball over,'' White said. ''We see defence as an opportunity to attack.
''We've got some really quick players out wide, so if we turn the ball over and send the ball out wide, there's no reason why we can't tear teams to pieces.''
The Brumbies will play two games in South Africa. They'll start against the Sharks before moving to White's home town - Cape Town - to play the Stormers next week.
When they return to Canberra, they will clash with two more South African teams - the Pretoria Bulls and the Southern Kings.
The Brumbies have won their first three games against Australian opponents.
''I don't think you have to change too much going up against South African teams,'' White said.
White has taken a 26-man squad to South Africa for the two matches.
Lock Etienne Oosthuizen and Zack Holmes are part of the
squad, while Wallabies Pat McCabe (hamstring) and David Pocock (knee)
stayed in the capital.