Nga Tawa even led 10-9 at quarter time before both Horrocks and Murphy began to leave their mark.
However, from a 16-11 advantage the dynamic changed after Murphy got entangled with Nga Tawa goal keep Georgia Nugent-O'Leary and went over on her knee in agony. After their tall timber was helped off, WHS knew they could be dragged into a tight dogfight but a reshuffle made virtue out of necessity.
Representative player Ashlee Murphy came on to goal shoot with Porchers Marsters joining her while Ruhia Tamati went to goal defence.
The new Murphy GS did not initially have the same accuracy percentages, but she was more than capable of latching on to her rebounds, while at the other end Tamati and Kuruybaki gelled exceptionally well when they cleared the circle.
By contrast Nga Tawa lost a bit of patience and made costly fumbles and the five point buffer remained at halftime, 22-17, then extended out of reach at 31-23 at the three quarter mark.
A Nga Tawa injury saw Nugent-O'Leary switch to goal attack, but matters did not improve for her team as the scoreline blew out to 40-24.
Horrocks marshalled superbly but again WHS saw what injury can cost when she took a heavy spill at the back end of the quarter and had to be carried off with an icepack on the ankle.
Upsets dominated the other games of the opening round with defending champions Wanganui Car Centre Kaierau A1 going down 32-30 to Collegiate A, while competition newcomers East Club Sports Edge beat against Marist A1 41-32.
Collegiate coach Nicole Dryden said it was a pleasing result that would give confidence to the girls that they could play the longer [one-hour] game.
"It was a close encounter throughout and we were down a point or two in the first few quarters, but we made changes at half time which gave us turnovers. There were also a few niggling injuries in both sides that probably affected the game," Dryden said.
East Club Sports Edge coach Trish Anstis praised her circle defence and circle feed.
"Our third quarter wasn't that flash, but our circle defence was outstanding with Amira Paranihi and Terehia Gardiner doing some very good work, while Karaihi Peina at wing attack fed well into the circle," Anstis said.
The newcomers finished second of seven teams during the grading games to gain a spot in the premier division this season.