Gloucester booked their place in the LV= Cup final on Sunday thanks to a fine 29-18 away win over Cardiff Blues.
The Cherry and Whites had lost 50-12 to the Blues in last year's Anglo-Welsh final and had suffered a 26-25 defeat against the Welsh side in the pool stages of this year's competition, but they were not to be denied.
The sides were locked at 10-10 at the break. Former New Zealand centre Casey Laulala going over for the Blues while full-back Freddie Burns crossed for the Cherry and Whites. Ben Blair and Nicky Robinson kicked five points apiece.
But a hat-trick from Simpson-Daniel put the visitors out of sight, meaning Ceri Sweeney's late try was little consolation for Dai Young's side.
The away side made an assured start with former Cardiff fly-half Robinson being successful with one of two early penalties to open the scoring, but the Blues quickly hit back with a penalty of their own from full-back Blair.
Wales wing Tom James came close to the opening try of the game as the Blues settled. Showing great pace to break clear, chip Burns and crash over the line. But video referee Tony Rowlands ruled that he had lost the ball over the line.
However, there was no doubt about Laulala's try.
The Kiwi made a clean break through the heart of the Gloucester defence and stepped Burns brilliantly to dot down under the sticks. Blair added the conversion.
But some ill-advised adventure from the home side allowed Gloucester to level the scores on the stroke of half-time. Sweeney looked to move the ball wide with a cut-out pass but it was picked off by Burns who sauntered over the line for a try converted by Robinson.
And Gloucester carried that momentum into the second half as, after Blues' flanker Ben White was sin-binned for slowing down the ball, they moved the ball right after a quick-tap penalty for Simpson-Daniel to get over out wide, Robinson producing a brilliant touchline conversion.
The Blues responded with a spell of pressure of their own and Blair kicked his second penalty to narrow the deficit to 13-17.
But that was as close as Cardiff got as flanker Akapusi Qera fed Simpson-Daniel for his second, and a Burns chip then gave the former England winger his treble.
Good work from Laulala put Sweeney in for a try two minutes from time. But it was not enough for the Blues, who now face a battle for Heineken Cup qualification through the Magners League.
For Cardiff Blues:
Tries: Laulala, Sweeney
Pen: Blair 2
Tries: Burns, Simpson-Daniel 3
Con: Robinson 3
Cardiff Blues:15 Ben Blair, 14 Tom James, 13 Casey Laulala, 12 Dafydd Hewitt, 11 Chris Czekaj, 10 Ceri Sweeney, 9 Gareth Cooper, 8 Xavier Rush, 7 Ben White, 6 Andy Powell, 5 Paul Tito (Capt), 4 Scott Morgan, 3 Scott Andrews, 2 T Rhys Thomas, 1 Faao Filise.
Replacements:16 Huw Dowden 17 Ian George 18 Nathan Trevett 19 Andries Petorius 20 Maama Molitika 21 Darren Allinson 22 Sam Norton-Knight.
Gloucester: 15 Freddie Burns, 14 James Simpson-Daniel, 13 Mike Tindall (c), 12 Eliota Fuimaono-Sapolu, 11 Lesley Vainikolo, 10 Nicky Robinson, 9 Dave Lewis, 8 Jake Boer, 7 Akapusi Qera, 6 Peter Buxton, 5 Alex Brown, 4 Will James, 3 Paul Doran-Jones, 2 Olivier Azam, 1 Nick Wood.
Replacements: 16 Darren Dawidiuk, 17 Rupert Harden/Alasdair Dickinson, 18 Pierre Capdevielle, 19 Adam Eustace, 20 Andrew Hazell, 21 Jordi Pasqualin, 22 Tim Molenaar, 23 Tom Voyce.
Referee: George Clancy