The Waratahs secured back-to-back Super Rugby wins for the first time in almost a year and a half on the Gold Coast.
The Waratahs scored 38 points without reply in the first half as they cut loose in the rain to thrash the Reds in Sydney.
Rob Simmons is on his way out of the Waratahs after agreeing a deal with ambitious Premiership club London Irish.
The Waratahs have been struggling to find form and a resounding defeat to the Rebels also came with an injury setback for their captain.
The Brumbies made it two wins from two in Super Rugby AU as a late try from Issak Fines saw them beat the Waratahs.
The Reds made it two Super Rugby AU wins out of three, but they were pushed all the way by the Western Force.
Western Force made a flying start in their first Super Rugby AU game, but the Waratahs fought back to secure the victory in Sydney.
The scores were level in the closing stages at Suncorp Stadium, but James O'Connor's penalties saw the Reds past the Waratahs.
After a three-month suspension due to coronavirus, Super Rugby will return in Australia from July 3, albeit in a revamped format.
Kurtley Beale and Luke Jones are returning to Europe to join top 14 heavyweights Racing 92 next year.