A looping ball over the back four looked harmless enough but Pamment over-committed outside his area and was left stranded as Zane Christianson reacted quickly to score.
Worse was to come when cheeky winger Paulio Montino spotted Pamment off his line from fully 40 metres out and sent the ball into the top left corner.
To Tauranga's credit, they played their best football trailing 3-1 and it was no surprise that the league's top scorer Jack McNab kept his composure in the box to stroke the ball past the keeper.
Earlier in the second half, McNab had opened the scoring with a superbly timed jump and header between two defenders from an inch perfect cross from the right touchline by McNabb's WaiBop United teammate Josh Nelson.
Tauranga had the best of the final 10 minutes of frenetic action but the finishing from his teammates lacked McNab's sharpness and focus.
At least the second half was lively and produced plenty of goalmouth action and five goals, after a turgid first half that was blighted by poor ball control and aimless passing.
The loss takes the gloss of what has been a fine middle to end of the season for Tauranga City after they started with four losses and a draw in their opening nine matches.
The squad have plenty of depth and talent, so if coach Duncan Lowry can retain most of the players over the summer into next season then they will be definite promotion contenders.
McNab's two goals took his season tally to 28 and he is seemingly assured of winning the prestigious Golden Boot Award as the league's top scorer with one game left to play.
He began the game on 26 goals, with Mangere United's Mario Hofmann back on 20 and his teammate Ernesto Lopez with 18 goals.
Tauranga City 2 (Jack McNab 2) Fencibles United 3 (Peter Jones, Zane Christianson, Paulio Montino) Halftime 0-0.