The great unknown for all but one of the AJC Australian Derby contenders is their ability to run a strong 2400 metres.The great certainty for trainer Bede Murray regarding Coniston Bluebird is his ability to run a strong 2400 metres.Coniston Bluebird proved his staying mettle with victory in last month's New Zealand Derby but punters have rallied to others in Saturday's Classic at Randwick.That's fine with the veteran NSW south coast trainer who won the 2001 Derby with Universal Prince who, like

The great unknown for all but one of the AJC Australian Derby contenders is their ability to run a strong 2400 metres.

The great certainty for trainer Bede Murray regarding Coniston Bluebird is his ability to run a strong 2400 metres.

Coniston Bluebird proved his staying mettle with victory in last month's New Zealand Derby but punters have rallied to others in Saturday's Classic at Randwick.

That's fine with the veteran NSW south coast trainer who won the 2001 Derby with Universal Prince who, like Coniston Bluebird, is a son of Scenic as is Melbourne Cup winner Viewed.

"He hasn't gone backwards since New Zealand and I couldn't be happier," Murray said.

"I know he can run the distance and he worked exceptionally well at Kembla Grange this week.

"I know he can run the distance and I know he can run it on a wet track if he has to.

"There's a few others in the race who don't tick as many boxes."

Murray believes Predatory Pricer is among those with a few question marks even though a win by him will still be cause for a family celebration.

Murray's son Paul prepares Predatory Pricer who is a half-brother to international sprint star Takeover Target.

"I think Predatory Pricer is potentially the best horse in this race but I really think my horse stays better," Murray said.

"And I think there is also a question over Sousa at the distance."

Spring Champion Stakes winner Sousa was promoted to outright favouritism when he drew barrier one and former equal favourite Metal Bender came up with gate 14.

New Zealand raider Harris Tweed came into contention with victory in the Tulloch Stakes over Derby rivals Dr Doute's and fellow Kiwi Old Jock.

Neither Harris Tweed nor Old Jock contested the New Zealand Derby on March 1 but Murray said he was pretty sure he had the form from across the Tasman covered.

"They (New Zealanders) didn't worry me over there, they are not going to worry me over here," he said.

Coniston Bluebird was at $12 on Thursday with Sousa at $4.40 and Metal Bender easing to $5 in his bid to win the triple crown.

The Jack Denham-trained Metal Bender was equal with Sousa at $4 until the barrier draw.

Sousa finished seventh in the Randwick Guineas (1600m) won by Metal Bender then improved to get within a half-head of him when stepped up to the 2000 metres of the Rosehill Guineas.

The Gai Waterhouse-trained Rock Kingdom, placed in both the Randwick and Rosehill Guineas, has been the best-backed Derby runner, firming from $12 on Tuesday to $6.50.