Super filly rocks boys in Derby

Danny O'Brien's willingness to test Shamrocker against the boys paid big dividends again when the filly took out the AJC Derby at Randwick.

A shrewd move at the 800m by jockey Glen Boss put Shamrocker ($5) within striking distance on the turn and she was able to wear down Retrieve ($8) to win by a length and a quarter, with another three and a quarter lengths back to third-placed Anacheeva ($21).

Shamrocker has made a habit of beating male rivals. She won last year's Group 2 VRC Sires Produce Stakes and then became only the third filly to win the Australian Guineas at Flemington last month.

She is the first Australian Guineas winner since Mahogany to take out the Randwick Classic.

Shamrocker has broken a drought stretching back to Research in 1989 for fillies in the Derby.

It had also been 22 years since a Blue Diamond winner had completed the Golden Slipper double before Sepoy's success last week.

O'Brien, whose biggest success to date was the 2007 Caulfield Cup quinella with Master O'Reilly and Douro Valley, had his first Group 1 win when Porto Roca won the 2001 Coolmore Classic. This is his first Group 1 win in Sydney since.

"It's a great honour and I am really thrilled," O'Brien said.

"If you look through the Derby, all the great horses, the great trainers and great jockeys are on that list, so I am very privileged to be on there, particularly the 150th running.

"It's always that little bit more special with these staying horses, because you have to take more time and everything needs to go to plan and it has."

Shamrocker will back up in next week's AJC Oaks, a race which Research also won.

"That was only her fourth run for the autumn today and we were always looking to have her peaking at Randwick," O'Brien said.

"She ran twice at the VRC carnival and we have seven days now, so I see no reason why she won't be full of beans next Saturday."

Shamrocker was bought out of New Zealand by O'Brien's bloodstock agent Karl Brown, a Queenslander formerly with the Magic Millions company before joining O'Brien four years ago.

"I had gone back to Melbourne and Karl said he had found a really nice O'Reilly filly," O'Brien said.

"I hadn't seen her but I left Karl there to have a really good look at the Select catalogue and he said there's only one we want. Any decent sort of O'Reilly I am happy to be involved in."

The filly cost only $65,000 and continues the trainer's brilliant run with progeny of O'Reilly.

"Every O'Reilly we've had, they don't get to their top until they turn five," O'Brien said.

"Master O'Reilly won a Caulfield Cup at five and Vigor ran third in the same race as a five-year-old. This filly is well ahead of schedule."

The win gave Boss his third victory in the Derby, following earlier successes on Sky Heights (1999) and Starcraft (2004).

Boss thanked O'Brien for adhering to the owners' wishes in allowing him to get back on the filly after he ditched her in favour of Absolutelyawesome in the Rosehill Guineas.

Jimmy Choux could not repeat his Rosehill Guineas heroics and was a spent force soon after turning. The $2.30 favourite wound up sixth.

Story by Nathan Exelby, to view full Courier Mail story and Fox Sports Derby News Report click here

Montage Photos taken by Courier Mail, Herald Sun, The Age and Sydney Morning Herald