A relieved John Thompson has celebrated the winning return of First Seal at Rosehill while rival trainer Chris Waller has been left wondering about the future of Catkins.

The two high-profile mares met in Saturday's Group Two Millie Fox Stakes (1300m) with Catkins the $2.40 favourite ahead of First Seal at $3.60.

Catkins was there to defend her title while First Seal was having her first start for 10 months after a hoof ailment derailed her spring campaign.

With Skyline Blush assuming the lead from Press Report, Catkins stalked the pair and tried to make her move in the straight.

But her customary finish failed her with First Seal the one with the momentum on the outside.

First Seal went on to beat Telepathic ($10) by three-quarters of a length with Catkins last of the six runners, three lengths from the winner.

"It's a relief," Thompson said.

"She's had a long time off and just to see her back is a thrill.

"There's still plenty of improvement in her and we'll send her to the Group One Canterbury Stakes next and just see where we go after that."

The Canterbury Stakes in two weeks could be a target for Catkins if Waller is happy enough with her.

"We'll take her home and go over her," he said.

"She doesn't run bad races and today she has run a bad race.

"We will have to decide whether to give her another run, over the 1400 metres, and if she fails again whether it should be the end.

"She's not going to race if she can't be competitive."