Victory showcased Blackmore’s skills in the saddle, showing patience when sat behind a group of horses and using her mount’s pace to perfection, jumping to the front over the last and powering clear.
It was the biggest winning distance since Master Oats in 1995.
The Festival’s all-time leading jockey, Ruby Walsh, said Blackmore was an inspiration to young female riders.
“She is the type of role model the sport needs,” said Walsh. “She is box office.”
Blackmore had followed up last year’s historic Champion Hurdle victory on Honeysuckle with a second success on Tuesday.
While last year’s meeting was held behind closed doors because of Covid-19, this year she was greeted by raucous cheers from a sell-out 70,000 crowd.
“To have that roar back and to get to walk back in when you can’t see space, and you can just see bodies, is just incredible,” she said.
“It is the closest thing to feeling like a rock star you will ever feel without being able to sing. It is just incredible to have people back and I feel very, very lucky. ”
The strides Blackmore and other women have made are illustrated by the fact that in 2017 Lizzy Kelly was the first female rider for 33 years to compete in the Gold Cup.
“When I took out my licence, I didn’t think I would be riding at Cheltenham, let alone a favourite in the Gold Cup,” said Blackmore.
“I’m so lucky to be getting the chance to ride horses in these kinds of races. This is the Gold Cup, you know what I mean?”