The daughter of Montjeu was dropping down in grade and deserved this breakthough success.
Jockey Dominic Fox did well to settle Panettone in a handy position as she broke from the widest stall of all.
He took over the running with half a mile to go and asked Panettone to stretch down the hill.
The runners were well strung out behind and Panettone kept up the gallop to win by nearly four lengths.
Roger said: "She is a well-bred filly so winning a race with her means a lot. Dominic has given her a good ride and she has done it nicely."