Mark Zahra may not be down in the record books as having ridden a Blue Diamond Stakes winner, but he knows what one feels like.

Zahra rides the $2.20 favourite Fontiton in Saturday's Group One race at Caulfield and has partnered the unbeaten filly in all her three starts.

It was a similar situation in 2011 with Zahra steering Sepoy to three consecutive wins in the lead-up to that year's Blue Diamond.

The only problem for Zahra was that he was replaced by Darley's No.1 rider Kerrin McEvoy for the grand final.

"I always knew he (McEvoy) was going to come down to ride him," Zahra said.

"It did hurt a touch after winning the lead-ups on him and then watching someone else win on him, but that's life I suppose."

Zahra described Sepoy as a little colt that was quite robust and strong and Fontiton as a little filly, but said both have one thing in common - acceleration.

"Sepoy was outstanding and then went on to win the Slipper which they rarely do," Zahra said.

"She's got to go out now and do it on Saturday."

Zahra goes into the $1 million Blue Diamond confident he's on the best horse in the race and with faith in the filly's ability.

But he's not getting overawed with the prospect of landing his first Group One win since Albert The Fat won the Emirates Stakes at Flemington in 2011.

"This is probably the biggest build-up being on an unbeaten filly going into the biggest two-year-old race in Victoria, but I'm not one to get overwhelmed by pressure and now's not the time to start," he said.