"She is just getting more mature and Opie took bad luck out of the equation when he popped off the fence and went three wide.
"He knew what he had underneath him, as he's ridden horses like this all his life, and he knows what to do on the big days."
Walker doesn't have any set plans for the filly but will take into consideration how she pulls up from the run before making any further decisions.
"We will see how she eats over the weekend and we trot up every horse who races on the weekend on a Monday.
"We'll have a good think about what happens next, but she did go to Riccarton in the spring, so maybe a break is in order. We have a few going to Brisbane but we'll just have a think about it after what we see on Monday."
Connections of Imperatriz could also potentially target the Group 1 Empire Rose Stakes (1600m) at Flemington in spring, where an A$1 million bonus is now in play.
The NZ Thoroughbred Breeders' Stakes is one of 12 black-type races whereby the winner is eligible for the seven-figure bonus should they go on to win the Flemington feature.
The Thoroughbred Breeders' Stakes was also the only domestic Group 1 race champion jockey Bosson had not won but he made all the right moves aboard Imperatriz to record the 87th elite-level victory of his career.
"We went out with an open mind, and if I lead, I lead, but they were going quick enough that I could take a sit," Bosson said.
"I was pleased that I could get off the fence when I could, although I did wonder if I had gone too soon.
"But I had a lot of lower-rated horses in front of me and wanted to clear them as soon as I could.
"I had a lapful of horse and I think she could even get further, as she relaxes so well and will get even stronger as she gets older."
As well as his domestic tally, Bosson has won a further 10 Group 1 races in Australia.
- NZ Racing Desk
