The Makos looked like they, not the six-time defending champions, were the more experienced playoff side tonight in Nelson, controlling much of the match and holding their Super Rugby partners to a pair of penalties.
Tasman will now take on Taranaki in next Saturday's Premiership decider in New Plymouth, a date that arrives one short year after winning the Championship to earn promotion.
Next week's showpiece match will ensure a brand new winner of the provincial rugby crown. Taranaki have never made a top tier final was Tasman have existed for only nine years.
The Makos are just three seasons removed from a 2-8 season that left them last in the Championship but they must now be considered among the true forces in New Zealand rugby.
Tasman won seven games this season, emerging from the round robin with the best points differential among any of the competition's 14 teams, and their berth in the final is more than deserved.
To get there, Tasman had to beat Canterbury twice in a fortnight. Tonight's game wasn't quite as comprehensive as their 38-10 victory earlier in the month but the result was the same.
And it was a result that means Canterbury's incredible streak of success has officially come to a close. Six straight titles speak for themselves but the extent of Canterbury's supremacy can be represented by the fact only one player in their squad - No 8 Nasi Manu - knew previously what it was like to lose a semifinal.
But the cracks in Canterbury's dynasty began to show last month. While a slide of three straight defeats was arrested with an impressive victory over Taranaki last weekend, Canterbury never looked like repeating that performance at Trafalgar Park tonight.
They were lucky to be behind to only James Lowe's second-minute try after a listless opening quarter, with Canterbury struggling to lift their heads after losing captain Willi Heinz in the warm-up.
While the visitors started to pull themselves into the game as the half wore on, enjoying better of both the ball and field position, a big bust from Robbie Malneek down the left-hand touchline eventually led to Jimmy Cowan's try on the stroke of halftime.
That effort saw Tasman take an 11-point advantage into halftime and it was a lead they never looked like ceding, with Canterbury handing their hosts plenty of assistance through stray passes and mental mistakes.
They were also ill-disciplined and three penalties from Marty Banks helped to keep the opposition at arm's length. The anticipated fightback from the finals-hardened Canterbury never eventuated and Tasman were eventually allowed to celebrate history.
The Makos will now attempt to add to that history by reversing their one-point defeat by Taranaki in round five.
Tasman 26 (Lowe, Cowan tries; Banks 2 cons, 4 pens), Canterbury 6 (Taylor 2 pens). HT: 17-6.
