Waratahs edged Brumbies 13-10 at the GIO Stadium to turn up the heat at the top of the Super Rugby Australian Conference.
The high-flyers were separated by just three points at the interval as Christian Lealiifano's boot helped the hosts into a 10-7 lead.
However, Waratahs fought back after the break, shutting their opponents out while assuming the lead thanks to penalties from Kurtley Beale and Bernard Foley.
Victory ensures Waratahs did the double over Brumbies for the second season running - extending their winning run in this clash to four matches.
It also puts the sides within a point of one another in the Australian Conference, as the holders move into the top six of the overall standings while Brumbies stay second thanks to their losing bonus point.
In the Friday's earlier game, Highlanders romped to a 48-16 victory over Sharks - the hosts running in seven tries at the Forsyth Barr Stadium in Dunedin.
Highlanders saw seven different scorers touch down as Sharks were outclassed, with Gareth Evans getting the scoring under way just three minutes in.
Elliot Dixon had the final say in his side's seventh victory from 10 matches as Highlanders registered their highest points tally in contests with their South African opponents.
It sets them up nicely for their upcoming tour, as Jamie Joseph's men prepare for clashes with Golden Lions, Cheetahs and Western Force.