Dunedin comfortably beat Pirates in the main semifinal at the University Oval, capitalising on every opportunity it had to score points.
The first try came after eight minutes when wing Tumua Ioane broke up the touchline deep into the Pirates 22m.
From the breakdown halfback Fraser Lau darted round the blindside to dot down.
Fullback Robbie Smith, besides being dangerous on the counter-attack, had his kicking boots on and landed four goals from his six attempts.
Dunedin was in complete control in the first spell and had shut Pirates out of the game.
Big lock Michael Gurran dominated the line-out and loose forwards Scott McKee, Tim Fraser and Jon Crossan were a devastating unit on attack and defence.
The first 30 minutes of the second spell was different with Pirates controlling play and making use of the wind at its back.
It camped inside the Dunedin 22m for long periods and kept hammering at the Dunedin line.
But the rugged Dunedin defence did not falter and flung back the repeated attacks.
Pirates' only try came after 22 minutes when centre Marshall Suckling, the best back on the paddock, burst down the touchline and replacement wing Isaac Beach was in support to score.
It was Pirates' tactics that stopped it from challenging Dunedin in the second spell.
In the first 15 minutes it turned down five easy shots at goal in a bid to score a try.
Dunedin took back control in the last 10 minutes of the game with its forwards camped inside the Pirates 22m.
It was rewarded with points when Gurran used his long arms to dive over the defence and score a try to make the game safe.
Dunedin 21 (Fraser Lau, Michael Gurran tries; Robbie Smith conversion, 3 penalty goals), Pirates 7 (Isaac Beach try; James Rosenberg conversion).
Half-time: Dunedin 16-0.
Referee: Ross Barnett.