"It's not a real rating, or anything, but that's why I gave her a 10 out of 10," he said with a grin as Sofia Rosa bolted clear to beat Strada Cavallo (Chris Johnson) by a shade of more than four lengths.
The Bay stayer was coming off a breather after winning the 2000m Group 2 Mongolian Khan Royal Stakes in Auckland on New Year's Day.
"She's had a freshen up and two months in between which was always a little bit of concern but she won very well today."
Remarkably the Masterton trainer felt Sofia Rosa still had potential to improve "bang on" for the group 1 Wellfield New Zealand Oaks in a fortnight in Wellington.
"She will improve as she was a bit light going into this, she was probably 90 per cent today," the Cambridge horseman said, championing yesterday's line up as arguably the best assembled in field of 16, after two scratches, for the past few years.
"She's a high-class filly and we expected her to be very competitive today, for sure."
Marsh has bracketed Sofia Rosa for a trip across to Sydney after the New Zealand Oaks.
"But her major aim is the New Zealand Oaks, the biggest 3-year-old fillies' stakes in the country and it"s group 1, at the highest level so we'll get that out of the way before working on the next plan of attack," he said.
A temperamental filly, Marsh said she incrementally improved with each preparation.
"She's just taken a long time to mature but today she's perfect."