The Brumbies beat the Waratahs 28-23 in Canberra after leading 25-9 early in the second half.
The hosts outscored their Sydney rivals three tries to two but were made to sweat in the dying minutes as the Waratahs fought back to narrow the gap to just two points.
The Brumbies' rush defence did an excellent job of shutting down the Waratahs backline, meaning dangermen Israel Folau and Kurtley Beale were rarely given a chance to stretch their legs.
Tries from Nic White and Jesse Mogg helped the Brumbies to a 20-9 lead at the interval.
A second-half score from Brumbies centre Tevita Kuridrani ensured that late tries for the Waratahs from Michael Hooper and Folau were not enough, despite the Brumbies conceding two yellow cards in the final quarter.
Brumbies – Tries: Nicholas White, Jesse Mogg, Tevita Kuridrani. Conversions: White (2). Penalties: White (3).
Waratahs – Tries: Michael Hooper, Israel Folau. Conversions: Bernard Foley (2). Penalties: Foley (3).
Brumbies – 15 Jesse Mogg, 14 Henry Speight, 13 Tevita Kuridrani, 12 Pat McCabe, 11 Robbie Coleman, 10 Matt Toomua, 9 Nic White, 8 Ben Mowen (c), 7 Jarrad Butler, 6 Scott Fardy, 5 Sam Carter, 4 Leon Power, 3 Ben Alexander, 2 Stephen Moore, 1 Scott Sio.
Subs: 16 Josh Mann-Rea, 17 Ruan Smith, 18 Jean-Pierre Smith, 19 Jordan Smiler, 20 Locky McCaffrey, 21 Andrew Smith, 22 Michael Dowsett, 23 Lionel Cronje.
Waratahs – 15 Israel Folau, 14 Alofa Alofa, 13 Adam Ashley-Cooper, 12 Kurtley Beale, 11 Peter Betham, 10 Bernard Foley, 9 Nick Phipps, 8 Wycliff Palu, 7 Michael Hooper, 6 Dave Dennis (c), 5 Kane Douglas, 4 Jacques Potgieter, 3 Paddy Ryan, 2 Tatafu Polota-Nau, 1 Benn Robinson.
Subs: 16 Tola Latu, 17 Jeremy Tilse, 18 Sekope Kepu, 19 Will Skelton, 20 Stephen Hoiles, 21 Pat McCutcheon, 22 Brendan McKibbin, 23 Rob Horne, 24 Matt Carraro, 25 Jonno Lance.
Photo: Stefan Postles/Getty Images