The three-year-old most likely to test It's A Dundeel before the autumn is over is the horse jockey James McDonald insists is an obvious benchmark in the $2.25 million BMW at Rosehill on Saturday.

McDonald continues his association with New Zealand mare Silent Achiever in the weight-for-age staying test in which the Victoria Derby winner Fiveandahalfstar is a clear-cut favourite to beat his older rivals.

The young jockey has claimed the Randwick and Rosehill Guineas on It's A Dundeel and he admits he will be interested in the outcome of the BMW for more than one reason as he looks ahead to a clash with Fiveandahalfstar in the Australian Derby.

With tongue firmly in cheek, McDonald said: "Hopefully Fiveandahalfstar has a bit of a gut-buster leading into the Derby.

"But still, he's a classy customer and he's going to be making his own luck out in front in the BMW and he's going to be hard to beat."

While Fiveandahalfstar is a clear BMW market leader at $2.80, Silent Achiever is a $10 chance after starting second favourite in the traditional lead-up race when she finished a disappointing fifth in the Ranvet Stakes.

But McDonald believes an improved track gallop at Randwick on Tuesday morning was enough evidence for him to declare the only mare in the field will be in mint condition on Saturday.

"I think her best bit of work this preparation was on Tuesday," he said.

"She needed the run last start because you could tell when she got to the furlong marker she really peaked on her run.

"I reckon she's spot-on for her race this time and going on her work she is definitely going to give the favourite a run for his money."

Half of the BMW field is made up of horses who started their racing careers in the northern hemisphere but it is another Australasian-bred stayer who is closest to Fiveandahalfstar in latest markets.

The 2010 Melbourne Cup runner-up Maluckyday is on the second line of betting at $6.50, just ahead of Chris Waller's Ranvet Stakes winner, the imported stayer Foreteller ($7).

Former German stayer, Hathras, is a $9 chance to complete what would be a remarkable rise after winning a Sydney midweek staying race against three horses at his most recent appearance.

Trainer Kris Lees has tinkered with entire's racing gear, adding winkers in a bid to help the four-year-old concentrate as he takes a serious leap of faith into stakes company for the first time.