Mornington trainer Amy Johnston says you miss 100 per cent of the chances that you don't take.

For that reason Johnston and the owners of $301 outsider Skyfire are taking on champion mare Winx, and five other rivals, in the Group One Turnbull Stakes (2000m) at Flemington on Saturday.

"I've got wonderful owners in this horse, Geoff Guest and Jill Kewish of Rockmount," Johnston said.

"They bred this horse and in horse racing, anything can happen.

"It could end up a three horse race on Saturday and all of a sudden he could run third in a Group One."

Rockmount is a racing and breeding operation that also provides pre-training and rehabilitation services.

With a rating of 61 Skyfire is the lowest-rated runner in Saturday's race, 23 points behind Magicool and 71 points lower than Winx.

Social media commentary has questioned Skyfire's place in the field, but Johnston couldn't care less.

"The people I care about are my owners and they've wanted to have a crack and that's what we're doing," Johnston said.

"Every horse in Australia and every trainer had the opportunity to throw a nomination in if they so desired.

"We decided we'd like to take up that opportunity and give the horse a chance of earning some money because he's not going to do that standing in his stable on Saturday."

Last year Winx defeated Black Heart Bart and He Or She in a three-horse field in the Caulfield Stakes and Johnston was hoping for a similar field sized on Saturday.

She kept a watch on acceptances as they rolled in on Wednesday morning.

"There was only four for quite a while and then a couple of others jumped in at the last minute," she said.

"We are under no illusions of grandeur. We don't think for a second that we're going to compete with Winx, there's barely a horse in the world that can at the moment.

"Our horse stays and is fit and well and we know he'll run out a strong 2000 metres and he'll pick up some nice prize money for the owners."

Following a $5500 acceptance fee, Skyfire will pick up a minimum $10,000 if he finishes sixth or seventh on Saturday.

It grows to $12,500 for fifth, $22,500 for fourth, $45,000 for third and $90,000 for second.

And if the unthinkable happens and Winx, chasing her 21st consecutive win, is beaten and Skyfire turns in one of racing's greatest upsets, first prize is $300,000.

"It is a horse race and anything can happen," Johnston said.