Brenton Avdulla rode his first Melbourne Group One winner on Saturday and might not have to wait long for another.

Avdulla, who rode the Gerald Ryan-trained Snitzerland to victory in Saturday's Lightning Stakes at Flemington, has turned his attention to winning the $1 million Blue Diamond Stakes on her stablemate, unbeaten colt Rubick.

It's a position Avdulla didn't think he would be in just a few months ago.

"Three or four months ago I was there thinking that I didn't have a carnival horse," Avdulla said.

"Arinosa was the one. She's probably not Group One quality but she's been a very good mare to me and how far she could take me, I wasn't quite sure.

"So three months ago I was heading into the Melbourne and Sydney carnival with nothing. I just stuck solid with Gerald and the two-year-old (Rubick) appeared and then the ride on Snitzerland appeared."

Rubick has made a big impression in a short time and heads into Saturday's Blue Diamond (1200m) at Caulfield as one of the most talked about youngsters along with unbeaten filly Earthquake.

The pair won their respective Blue Diamond Preludes in identical times.

Avdulla admitted he was nervous heading into the Lightning on Snitzerland, but after getting the job done he said his focus would switch to the Blue Diamond with Rubick.

"Now it's exciting to go there on Saturday confident that I've got a horse that can definitely win a Group One as well," he said.

Rubick will have his main piece of work ahead of the Blue Diamond at Caulfield on Monday.

The Peter Snowden-trained Earthquake is the TAB fixed odds favourite at $2.80 slightly ahead of Rubick at $3.

"It looks a match race on paper, but I don't think that," Avdulla said.

"They are two-year-olds and anything can happen. A few of the horses that ran behind Rubick in the Prelude ran very well but I'm on a horse that's blessed with a lot of ability and I think he's a potential topliner.

"Whether we see that topliner there next week or next preparation, I'm not sure. But hopefully we see the real deal there on Saturday."