Dunn has a big opinion of Rocknavar who jumps in class in the Group Three Adrian Knox Stakes on Saturday.
“She has drawn barrier 17 and I don't really know what that will mean on a wet track. But I have got Jason Collet to ride her and he is in great form,” Dunn said.
“Her trial was very good when second at Rosehill recently. I don't think she will disgrace us.”
Dunn paid $300,000 for the Fastnet Rock filly and is hoping she can confirm her place in the Australian Oaks (2400m).
Rocknavar has won her past two starts with the latest over 1800m on a testing Eagle Farm track on March 9.
“Things have gone well with her and we just don't want it too wet,” he said.
Collett will also ride La Scopa who won a heat at Grafton impressively at her most recent start.