First five-eighth Michael Witt showed his full range of skills as he helped Taieri claim its biggest scalp since re-entering the ranks of premier club rugby.
Witt set up two tries, defended well and kicked accurately to space, even if he did miss two conversions he would normally have nailed.
The former Warriors league star has been under the microscope since his move to Otago rugby, and Saturday was a major litmus test as he faced Pirates pivot Glenn Dickson, one of the two best first fives in the province.
Witt passed with flying colours - his growing confidence in his new code is obvious - while Dickson did not have one of his better days.
Taieri was subdued in the first 20min but completely dominated the rest of the game, with lock Callum Bisset winning the aerial battle and Witt's fellow league convert, Ryan Shortland, ruling the midfield.
Tom Davie, the former triple jump champion turned aspiring bobsledder, popped up at the right time to score two good tries on the wing for Taieri.
Pirates had appeared to be coming into form in recent weeks but it suffered a meltdown on Saturday.
In a side plagued by handling errors and average decision-making, only hard-driving No 8 Warren Kearney could take any consolation from his performance.
Taieri 30 (Ryan Shortland, Tom Davie 2, Matt Sims tries; Matt Witt 2 conversions, 2 penalty goals), Pirates 13 (Anthony Teaupa try; Glenn Dickson conversion, 2 penalty goals).
Half-time: Taieri 17-10.
Referee: Doug Rodgers.
Taieri 30
Pirates 13
