First-five Bernard Foley scored a brilliant late try and kicked 11 points to fire the Waratahs to a 26-8 victory over the Brumbies in Sydney and into their third Super Rugby final.
Foley finished off a breakaway move that started deep inside the Waratahs own half four minutes from time to seal the win and a home final next weekend against the Crusaders, who beat South Africa's Sharks 38-6 in the earlier semi-final.
The Waratahs, who lost both their previous finals to the Crusaders in 2005 and 2008, had been set on the path to victory by opportunistic tries from winger Alofa Alofa and centre Kurtley Beale at the start of each half.
The Brumbies, beaten finalists last year, played a full part in a hugely physical contest but were only able to cross once through winger Henry Speight in the 31st minute and failed to score after the break despite dominating possession.
The Brumbies were still pounding away at the home defence in the 75th minute when the Waratahs snapped up a wild inside pass from winger Joe Tomane about 15 metres from their line.
Hulking second rower Will Skelton came into the move in midfield and bulldozed 20 metres through the defence with tacklers hanging off him before offloading to Foley, who took the ball at pace to touch down and delight most of the 38,800 crowd.
It was a sparkling finish to an all-Australian semi-final that had promised attacking flair but delivered crushing tackles and dogged defence.