Peter Snowden isn't keen on a Cox Plate start for Guelph despite the filly continuing a brilliant run for the Darley team with victory in Wednesday's Group One Thousand Guineas at Caulfield.

Guelph became the first filly since 1996 to win the Flight Stakes-Thousand Guineas double with an all-the-way victory in the 1600m fillies feature.

Snowden said a final decision on a Cox Plate start would be made by owner Sheikh Mohammed in the next few days.

If Guelph does go there she will join stablemate and Caulfield Guineas winner Long John in the race.

"It's not my call alone. It's a team decision," Snowden said.

"I've made it known all along I'd like to stop with her now but the boys will have a talk and we'll talk to the boss and see what he thinks.

"We'll come up with the right decision I hope."

Guelph was sent out a $1.45 favourite and jockey Kerrin McEvoy took the race by the scruff of the neck from the outset, bouncing to the front where the filly dictated terms.

She kicked around the home turn and when May's Dream ($7.50) challenged her early in the straight, Guelph found another gear to again surge clear and score by 1-3/4 lengths with 2-1/2 lengths to Gregers ($10) third.

Guelph's second Group One of the season and her fourth overall continued a golden period for Darley's three-year-olds in Group One races.

Long John won the Caulfield Guineas on Saturday and Complacent collected the Spring Champion Stakes in Sydney on the same day.

McEvoy became the first jockey since 2002 to win the Guineas double at Caulfield in the same season while Snowden is the first trainer since Bart Cummings in 1996 to achieve the feat.

Snowden was effusive in his praise for Guelph who he rates alongside Forensics as the best filly he has trained.

He believes the best of her will be seen next autumn.

"She's a very, very good filly and she's got a great attitude to go with it," he said.

"She's very tradesman-like. When the second horse came to her she kicked and if anything else came at her she would have kicked again. She's just got that quality that she'll keep finding."

Snowden said Darley's recent run of success had been two months in the planning.

"When we were going through a quiet time we kept saying to ourselves as a team, `we know what we've got and we've just got to hope they come up as well as we think they will'. And they did," he said.

"It's good when a plan comes off."