"Forget that she went around at Ellerslie last-start (where she finished last). It's hard to say now, but I'm glad I made the decision not to run her in the Karaka Million.
"I just felt everything went pear-shaped at Ellerslie and we just needed to regroup and come back a class and we got the result."
Jockey Lisa Allpress was critical of her ride in the race, but was relieved to get the win aboard the southern raider.
"It was probably the worst ride of my entire life," Allpress said. "The plan was to let her roll forward - she is pretty one dimensional.
"But the horse outside her (Scotch) didn't really let up. It kept coming with me and I really had to stay positive to hold that horse out.
"In the meantime, two kicked up on the inside, so we were just a victim of circumstances. To her credit, she is so tough. She just kept on finding. I couldn't really believe it.
"All these terrible things were going through my mind, but she just kept finding. The other horses came, but she just kept finding that kick - she is very brave."
It has been a successful juvenile season for Miss Federer, with the $10,000 Karaka yearling sale purchase also winning the Listed Welcome Stakes (1000m) at Riccarton in November.
Carston was thrilled with the result and said she could possibly head towards the Gr.2 J Swap Contractors Ltd Matamata Breeders' Stakes (1200m) later this month.