Taieri scored three tries in beating Alhambra-Union at Peter Johnstone Park, but it will need to brush up its play to beat University A in the semifinal.
The Taieri backline made many basic mistakes through risky passes and wrong options.
Promising movements had little reward because of loose passes at the end.
But there was promise because Ben Nowell was in top form and used his silky skills to tear the Alhambra-Union defence to ribbons.
Halfback Nick Roulston was tidy and centre Kori Rupene was always a danger with the ball in hand.
The forwards set up a good platform. Tighthead prop Brett Anderson had a strong game in the scrum, flanker Willis Scott was an effective link and a lethal spot tackler, and hooker Will Hurst was effective in broken play.
The best Alhambra-Union player was tighthead prop Scott Manson, who was solid in the scrum, effective with the pick and go and strong on defence.
He was backed by hooker Ben Pereira and No 8 Regan Turoa.
Second five-eighth Colin Davies was a strong defender and was the best Alhambra-Union back. Fullback Corey McFadzean was dangerous on the counter-attack.
Tries to lock Karl Bloxham and Scott gave Taieri a 14-3 lead at the break but this was reduced to one point, 14-13, when Manson scored after nine minutes in the second spell.
A Rupene try three minutes later gave Taieri the buffer it needed and it held on to its advantage with strong defence.
Taieri 24 (Kori Rupene, Willis Scott, Karl Bloxham tries; Hayden Parker 3 con, pen), Alhambra-Union 13 (Scott Manson try; Peter Breen con, 2 pen).
Halftime: 14-3.
