Australian Paul Tapner and Indian Mill finished third.
But it was Price's day, coming after her ninth placing at Burghley on The Deputy.
''I am absolutely delighted," Price said.
''She is a feisty little thing. She hasn't been the most straightforward, and won't be her whole career.''
It had taken Price a few years to try and work the mare out and harness the attitude into a positive.
"We are starting to see glimpses of that now, and we are certainly not at the finished product yet.
''She is as careful as a cat (while jumping) and has so much ability."
There could be an omen for Price too. The class she won today can be a precursor to bigger things.
Mark Todd (2010), Britain's world No 1 William Fox Pitt (2011) and Nicholson (2012) won this event and went on to win Badminton, Pau and Kentucky four star titles respectively on the horses.
In the three star event, Price's husband Tim was best of the New Zealanders finishing seven on Ringwood Sky Boy. Briton Francis Whittington on Easy Target won the title.