Also going clear of the 13 starters in the first round were Rose Alfeld (Christchurch) aboard My Super Nova, Katie Laurie (Mystery Creek) on Dunstan Lucca, and Helen McNaught-McFarlane (Taupo) on Carnutelabryere.
Those with eight faults or less came back for the second round where Maurice Beatson (Dannevirke) on Schimmel Warrior was clear but carried through four faults, and Olivia Robertson (North Canterbury) on Ngahiwi Cisco left everything up but had a time fault to finish on five faults from their two rounds.
Finishing second behind Morrison was McNaught-McFarlane, with Beatson third, Robertson fourth, Laurie fifth and Tash Brooks (Cambridge) on Kaapatack sixth.
Morrison was delighted with her win.
"Some of the lines were a little tricky but he coped really well. This win means a lot to me - it shows that we can compete at that top level and possibly go further. It is great to know I am sitting on a horse that can jump the top competition in New Zealand."
Morrison may have gleaned a little during the winter months when she travelled to the FEI World Cup final to watch Laurie compete on her mother's horse Frangipanne de Toxandria.
Today marked the start of the World Cup series in New Zealand. The six rounds will culminate with the final in mid-January at Waitemata.
Just the best four rounds count and those with more than one horse in the class must nominate which one will do well.
Today both Beatson and Laurie dipped out on World Cup points for nominating the wrong horses.
The winner of the New Zealand series has the opportunity to represent the country at the Longines FEI World Cup Jumping 2015/2016 Final, which is being held in Gothenburg, Sweden from March 23-28, 2016.
The class was also the first round of the Excel Premier League.