The Brumbies, who outscored the Stormers by a staggering six tries to one, will now meet the Hurricanes in Wellington next weekend, while in the other semifinal the Waratahs will host the Highlanders in Sydney.
For the Stormers their loss meant their sixth loss in seven playoff matches and they were simply exposed by Brumbies flank David Pocock on the ground, while the clever kicking game created big holes for the visitors in the first half and forced the Stormers into countless errors.
The killer blow was probably the second try scored by Brumbies No 8 Ita Vaea and the team’s fifth to send them into a 34-19 lead in the 62nd minute, but for the Stormers the writing was probably on the wall much earlier.
Fullback Jesse Mogg scored the sixth on the stroke of fulltime despite the Brumbies being left with just 13 men in the last seven minutes after a red card to wing Henry Speight – for a dangerous tackle on Stormers skipper Juan de Jongh – and a yellow card to Scott Fardy for a professional foul.
Leading 24-6 at the break the Brumbies outscored the Stormers by four tries to nothing in the opening half and exposed the hometeam at the breakdowns while their all-out running approach coupled with a tactical kicking approach found big holes out wide.
The Stormers started to climb their long way back with their only try by fullback Cheslin Kolbe four minutes after the break to narrow the gap to 24-13, while in the 48th minute Stormers flyhalf Demetri Catrakilis closed the gap even further with another penalty to make the score 24-16, before Brumbies pivot Christian Leali’ifano stretched the lead again in the 50th minute to 27-16.
Catrakilis’ fifth straight successful kick in the 60th minute brought the home team closer again to 27-19, but several butchered lineouts in the Brumbies’ red zone from attacking penalties cost the Stormers heavily.
But the big blows came earlier when the Brumbies stunned the home team with three tries by Tomane in the first half to race to a 17-3 lead by the 25th minute.
First Tomane pounced on a clever grubber by scrumhalf Nic White in the fourth minute to go up 5-0, before a hanging kick by centre Matt Toomua saw them turning over possession to send Tomane out wide for his brace and a lead of 10-3 by the 15th minute.
In the 25th Tomane easily handed off Stormers wing Dillyn Leyds to complete his hat-trick and while Catrakilis kicked two penalties to reduce the gap to 17-6, the Brumbies scored their fourth on the stroke of halftime by Vaea to go into the den with a big 17-point gap.