Damian Browne is banking on Missy Longstocking's relaxed attitude to help her cope with a stamina test in Saturday's BRC Sires' Produce Stakes.

Missy Longstocking earned mixed reviews when she won last Saturday's Lancaster Stakes at Doomben by a short head as a $1.65 favourite but her jockey has defended her performance.

"The win probably wasn't as impressive as a lot of people were expecting but a lot of credit should go to the second horse who really gave a good kick at the furlong and made us work for it," Browne said.

"She also ran a second faster than the boys did in the previous race so I can't see much that was wrong with the run."

Missy Longstocking has drawn gate one for the Sires' at Doomben which Browne believes is another crucial factor in her favour.

"She was three wide the other day but from the one alley she could be able to find a nice spot this time and she's such a relaxed filly it's going to make her task a lot easier," he said.

"Obviously the 1350 metres is the query but drawing the fence will mean she's not going to be covering any extra ground.

"If she'd drawn another bad gate and was going to be stuck three-wide like she was last week that was going to make it very difficult for her."

Trainer Liam Birchley won't commit to a start in the Group One JJ Atkins (1600m) at Eagle Farm on June 8 until he assesses her performance in the Sires'.

"She'd had have to be hitting the line and screaming out for the mile otherwise she'll spell for the spring," Birchley said.