The Rebels beat the Waratahs 24-10 in a drab Australian derby in Melbourne on Friday.
Rebels replacement wing Andrew Kellaway scored two decisive tries against his former team in the final six minutes of a game played in driving rain.
That enabled the Rebels to record a first triumph over the Waratahs since 2016 and get off the mark for the season following away defeats to the Sunwolves and Brumbies.
Rebels wing Marika Koroibete claimed the only try of the first half, after Matt Toomua and Will Harrison had exchanged penalties, but Harry Johnson-Holmes responded for the Tahs six minutes after the interval.
Harrison's conversion briefly nudged the visitors ahead, but a Toomua penalty put the Rebels back in front and the flyhalf split the posts again to make it 14-10 before Kellaway's late scores consigned the Waratahs to a third consecutive defeat this season.
Try: Marika Koroibete, Andrew Kellaway (2). Penalties: Matt Toomua (3).
Try: Harry Johnson-Holmes. Conversion: Will Harrison. Penalty: Harrison.
Match and player stats
15 Dane Haylett-Petty (c), 14 Reece Hodge, 13 Campbell Magnay, 12 Billy Meakes, 11 Marika Koroibete, 10 Matt Toomua, 9 Ryan Louwrens, 8 Isi Naisarani, 7 Richard Hardwick, 6 Michael Wells, 5 Matt Philip, 4 Ross Haylett-Petty, 3 Ruan Smith, 2 Anaru Rangi, 1 Matt Gibbon.
Subs: 16 Steven Misa, 17 Cameron Orr, 18 Cabous Eloff, 19 Gideon Koegelenberg, 20 Robert Leota, 21 Angus Cottrell, 22 Frank Lomani, 23 Andrew Kellaway
15 Kurtley Beale, 14 Cameron Clark, 13 Alex Newsome, 12 Karmichael Hunt, 11 Jack Maddocks, 10 Will Harrison, 9 Jake Gordon, 8 Jack Dempsey, 7 Michael Hooper, 6 Jed Holloway, 5 Rob Simmons (c), 4 Tom Staniforth, 3 Harry Johnson-Holmes, 2 Robbie Abel, 1 Angus Bell.
Subs: 16 Damien Fitzpatrick, 17 Tom Robertson, 18 Tetera Faulkner, 19 Ryan Mccauley, 20 Lachlan Swinton, 21 Mitch Short , 22 Lalkai Foketi, 23 Mark Nawaqanitawase.