It's been a slow process, but Extensible has shown her trainers she has the quality to tackle a stakes race by winning strongly at Rosehill.

The Peter and Paul Snowden-trained five-year-old won her third race from seven starts in a 1400m fillies and mares race on Saturday.

"She's been a long while coming," Peter Snowden said.

"She's been very light and immature but she's starting to get there now."

Snowden said Extensible was likely to run in another benchmark race to lift her rating so she could enter stakes races during the Melbourne spring carnival.

Jockey Kerrin McEvoy was able to get cover in the second half of the field on Saturday before allowing Extensible ($2.20 favourite) to sprint away to win by 1-3/4 lengths from Ladbien ($4.80), with Stilettoed Vixen half a length away third.

"I'm sure that she's going to stay further than the 1400 metres so there's options for her later in the spring," McEvoy said.