Rostova justified her high rating for the Blue Diamond Stakes with a slashing first-up win in a preview for fillies at Caulfield on Monday.The daughter of Testa Rossa had been regarded as the most impressive two-year-olds to race in Victoria so far this season on the strength of her debut win in the Schiavello Stakes (1000m) at Flemington on Melbourne Cup Day.She is now the $5 Blue Diamond favourite on the strength of her win in the Listed 1000-metre dash on Monday.A drifter in betting from $1.9

Rostova justified her high rating for the Blue Diamond Stakes with a slashing first-up win in a preview for fillies at Caulfield on Monday.

The daughter of Testa Rossa had been regarded as the most impressive two-year-olds to race in Victoria so far this season on the strength of her debut win in the Schiavello Stakes (1000m) at Flemington on Melbourne Cup Day.

She is now the $5 Blue Diamond favourite on the strength of her win in the Listed 1000-metre dash on Monday.

A drifter in betting from $1.90 to start a $2.6 favourite, Rostova, ridden by Steven King, settled back in eighth place of the 10 runners but picked up her rivals with ease, scoring by two-and-a-half lengths from first starter Irish Lights ($5.50).

Race leader Baby Corn ($21) held on well to be two lengths away third.

"I spoke with Steven (King) during the week and the feeling was even though she'd had a jumpout she was a bit vulnerable today," trainer Steven Richards said.

"She isn't quite there yet and if they couldn't beat her today well they won't beat her (again). There is plenty left in the tank.

"They were spruiking horses (to beat her) left, right and centre."

Richards said because Rostova does that well, she would definitely go on to the Group Three Blue Diamond Prelude for fillies over 1,100 metres at Caulfield on February 7, a fortnight before the Blue Diamond.

Richards said he strapped the 1975 Blue Diamond winner Lord Dudley in his days working for master trainer Bart Cummings.

He has had two unplaced runners in his own right, Coolmore Queen and Appleby Fair, but Rostova gives him a great winning chance.

King said Rostova had a bit against her, including the outside draw in the 10-horse field and not being fully wound up yet, but he was surprised with how easily she won.

"Filly-wise she's about the best two-year-old I've ridden. She's a pretty casual filly, she knows what it's all about and did everything right," he said.

Blue Diamond king Dwayne Dunn says he's no closer to picking his mount in the $1 million juvenile feature (1200m) on February 21 following his win on the Peter Moody-trained Reward For Effort in the colts and geldings preview.

With Moody's stable rider Luke Nolen currently under suspension and the Lee Freedman stable without a runner in the Listed colts and geldings preview (1,000m), Dunn was snapped up for the ride on the Exceed And Excel colt.

Making his racetrack debut, Reward For Effort ($6) settled fourth and raced clear in the straight, holding out the $3.70 favourite Rarefied comfortably on the line by one-and-a-quarter lengths.

First starter Bombay Sling ($5.50), who showed abundant speed to lead, was a long-head away third.

Dunn has won the past four Blue Diamonds aboard Undoubtedly (2005) Nadeem (2006), Sleek Chassis (2007) and Reaan (2008).

Being stable rider for Lee Freedman, he is likely to be aboard one of the Hall of Fame trainer's two-year-olds.

"I'll have to work out what I ride," Dunn said.

A $190,000 Melbourne Premier Yearling Sale purchase, Reward For Effort is out of the Rory's Jester mare Miss Prospect whose eight raced foals have all been winners, including Consular and Annie La Vie.

"He's a workmanlike colt and he got the job done in that style today," said Moody's stable manager Jeff O'Connor.

"He did chase and that's probably his best asset."