Stephen Perofeta, playing at first-five eight, set up the first try in an attractive fashion which Daniel Rona scored.
Taranaki continued to penetrate the Auckland line with confidence. It didn't help when Auckland lost key players Salesi Rayasi, Bryce Heem and Adrian Choat to injuries. More followed in the second spell.
Hooker Ricky Riccitelli scored from a driving maul before half time and Perofeta added two conversions and a penalty in the first half.
Auckland barely fired a shot apart from a penalty to Harry Plummer.
But it was the second half that was disappointing for Bulls fans.
Auckland stormed back in the driving rain, including two tries to Terrell Peita and AJ Lam.
Taranaki couldn't contain Auckland's attacking nature and the scrum, which was being shunted backwards by Auckland, a contrast to the previous three matches. Auckland dominated the second half possession obvious with their 35-7 score in the second stanza.
Kini Naholo scored Taranaki's only second half try, which was also set up by Perofeta and midfielder Daniel Waite.
Perofeta was probably on limited minutes by the All Black after being removed on the 60-minute mark, other reserves followed suit for Taranaki. Neil Barnes also made several second half changes which seemed to disrupt the flow for Taranaki.
Taranaki had a chance later in the game to score two tries, but with a wonky lineout throw and Jacob Ratumaitavuki-Kneepkens attempted a grubber-kick inside the 22, the opportunities went astray.