The Waratahs kept their chances of reaching the play offs alive when they beat Australian Super Rugby conference rivals the Brumbies 28-22 in Sydney.
The result ended a three match losing streak to the Brumbies for the Waratahs who last beat the Canberra franchise in 2011.
The Waratahs victory came with a cost though as Tatafu Polota-Nau went off just before half time and was later diagnosed with a broken arm ruling him out of the upcoming Lions tour and potentially the rest of the Super Rugby season as he will be looking at 4-6 weeks out.
George Smith also had to leave the field with a suspected medial ligament, injury that could keep him out for 6-8 weeks and Pat McCabe came off injured just before full time.
Former tournament leaders the Brumbies have now lost their last two matches and have a two point lead over the Reds who also benefited from the result as a victory over the Cheetahs later today with make them conference leaders.
The Waratahs fought back from 13-6 down at halftime in front of 21817 fans to overhaul Jake White's Brumbies with three second-half tries.
Playmaker Berrick Barnes proved influential coming off the bench at halftime to engineer the Waratahs' victory with a try and having a hand in another while kicking two conversions and a penalty.
The Brumbies controlled the opening half with tries to skipper Ben Mowen and centre Tevita Kuridrani to hold a seven-point lead at the interval, but the Waratahs were a different proposition with Barnes calling the shots in the second half.
Barnes put flanker Michael Hooper over in the corner and then scored himself before winger Peter Betham beat two tackles to score the clinching try five minutes from fulltime.
It was a horror night for Wallabies coach Deans watching from the stands as first Polota-Nau trudged from the field with his right arm cradled in his jersey just before halftime and then George Smith walked off midway through the second half.
Smith, who is on the verge of a remarkable comeback after playing the last of his 110 Tests four years ago, sat on the sidelines watching the remainder of the game with his left knee wrapped in an ice pack.
"That was really pleasing. We were off in a few areas, getting out of our own half and struggling in the lineouts, but to have that go on and still win the match is pleasing and we are developing a winning attitude," Waratahs skipper Dave Dennis said.
"The Brumbies and us lost a few key players and that probably upset their rhythm a bit, but it was always going to be physical, so you are going to get those injuries."
Brumbies skipper Mowen said Berrick Barnes was the difference after halftime.
"The game needed someone to grab it by the scruff of its neck and go on with it and Berrick did that superbly for the Waratahs," Mowen said.
"He controlled things well in that period, put them on the front foot and scored a great individual try and Betham on the back of that closed it out with his try."
The Brumbies cross the Tasman to face the Blues in Auckland next weekend, while the Waratahs are away to the Rebels in Melbourne.
Final Score Waratahs 28 (6) Brumbies 22 (13)
Tries - M.Hooper, B.Barnes, P.Betham
Pen - B.McKibbin 2, B.Barnes
Con - B.Barnes 2
Tries - B.Mowen, T. Kuridrani
Pen - C.Lealiifano, J.Mogg 3
Cards - T. Kuridrani 49th min (yellow)
Referee: Steve Walsh
Assistant Ref 1:Rohan Hoffmann
Assistant Ref 2:Graham Cooper
TMO : Peter Marshall
1. Benn Robinson , 2. Tatafu Polota-Nau , 3. Paddy Ryan , 4. Sitaleki Timani , 5. Kane Douglas , 6. Dave Dennis (c), 7. Michael Hooper , 8. Wycliff Palu , 9. Brendan McKibbin , 10. Bernard Foley , 11. Drew Mitchell , 12. Rob Horne , 13. Adam Ashley-Cooper , 14. Cam Crawford , 15. Israel Folau
Replacements, 16. John Ulugia , 17. Sekope Kepu , 18. Will Skelton , 19. Mitchell Chapman , 20. Matt Lucas , 21. Berrick Barnes , 22. Peter Betham
1. Scott Sio,2. Stephen Moore,3. Ben Alexander,4. Scott Fardy,5. Sam Carter,6. Peter Kimlin,7. George Smith,8. Ben Mowen,9. Nic White,10. Matt Toomua,11. Joe Tomane,12. Christian Lealiifano,13. Tevita Kuridrani,14. Henry Speight,15. Jesse Mogg
Replacements,16. Siliva Siliva,17. Ruan Smith,18. Fotu Auelua,19. Colby Faingaa,20. Ian Prior,21. Robbie Coleman,22. Pat McCabe.