Peter Snowden added to his Blue Diamond fire power with Mohave's Preview win at Caulfield on Saturday but the most impressive Diamond trial of the day wasn't in Melbourne.

The Snowden-trained Earthquake had been favourite for the Blue Diamond since betting opened but she was displaced on Saturday after the Gerald Ryan-trained boom colt Rubick powered to an impressive debut win at Randwick.

He moved to $3.40 Blue Diamond favourite with TAB fixed odds ahead of Earthquake ($4.20), who is due to step out in a trial at Cranbourne on Thursday before the Blue Diamond fillies Prelude on February 8.

Mohave, runner-up in the Breeders Plate in his only previous start, resumed in the colts and geldings Preview (1000m) at Caulfield on Saturday and passed his first Melbourne test with flying colours.

Snowden believes he can be a Blue Diamond player and has aimed him at the three race series.

The colt remained at $18 for next month's Group One Blue Diamond (1200m) while the Peter Morgan and Craig Widdison-trained Eloping, who made it two wins from as many starts with a one-length victory in the fillies Preview, moved from $21 earlier on Saturday to $15.

Mohave's winning time was 57.72 seconds while Eloping clocked 57.67sec in her all-the-way win.

Mohave ($4) settled just behind the leaders Stingray and Tudor and moved into the race strongly in the straight under jockey Chris Symons and held favourite Cornrow ($3.60) at bay to win by three-quarters of a length with 1-1/4-lengths to Ducal Castle ($6) third.

"He showed in his first start that he does most things right. He's blessed with natural pace early but he was strong late today," Snowden said of Mohave.

"I'm very confident he'll get a lot further than what today's trip was.

"He's been targeted for a Diamond and I think on Diamond day, providing he runs well next start, he should be there and be very competitive."

Snowden is delighted with the way Earthquake has settled into Melbourne and is keen to see her again in the Diamond Prelude having won impressively on debut in Sydney in November.

"She's a quality filly," he said.

Snowden was in Melbourne for Mohave's win but took notice of Rubick's 2-3/4-length win at Randwick in slick time (56.39s).

"I did see him. He's very smart," Snowden said.

"He backed up his trial."