Peter Snowden resisted the "I told you so" response after Guelph emerged as his stable's No.1 Blue Diamond contender at Caulfield on Saturday.

But he was entitled to gloat somewhat after the filly turned in a stunning performance in the fillies' division of the two Blue Diamond Preludes.

Snowden-trained runners have been staking their Blue Diamond claims almost weekly with the unbeaten Metastasio, another of Saturday's winners Kuroshio, and Montsegur all staking undeniable claims.

But Snowden has repeatedly batted away inquiries about that trio's Diamond prospects, consistently declaring Guelph to be his top pick.

And in her first run in Melbourne, Guelph justified her trainer's confidence.

Guelph ($2.25 fav) wasn't entirely comfortable in her Caulfield debut, but she still put away stablemate Montsegur ($3.40) without fuss, scoring untouched by 1-1/2 lengths.

Godiva Rock ($7.50) took third, a further 1-1/4 lengths away.

The win caused bookmakers to promote Guelph to a position from which she is expected to challenge long-time Blue Diamond market leader Miracles Of Life for favouritism.

Winning jockey Kerrin McEvoy said he needed to help Guelph around the tricky Caulfield bends, but only as much as he expected.

"I pulled her around the home turn a bit, but she really didn't have a problem," McEvoy said.

"The impressive part was that she bounced out and took a good spot.

"She did it all really well."

Guelph's win followed that of Kuroshio who scored a brave victory in the colts and geldings Prelude after sitting three-wide without cover for the entire 1100m.

His win put him firmly into a Blue Diamond picture that will contain at least three Snowden-trained runners and possibly four.

"I'll talk about it with the team first," Snowden said.

"But Guelph will definitely be there."

Kuroshio ($3.30 fav) overcame his chequered run to score by a neck from The Bowler ($8) with a short neck to Dissident ($3.40) in third.

Both the runner-up and the third horse will return for the Blue Diamond on February 23.

Adelaide filly Miracles Of Life who will be ridden by regular partner, apprentice Lauren Stojakovic, still holds a slight call in betting on the Group One juvenile feature at $3.10 with Guelph at $3.30 and Metastasio at $7.50.