Simon Rimmer's Blue Diamonds ($21) stunned the field in Monday's Ladbrokes Cash In Maiden (450 metres) at Bathurst when she bolted home to bring down Hay Pepper ($5.50, Frank Jeffcoat), who had looked a certain winner with 100m to go.

Blue Diamonds got away slowest from box three but it turned out to be a blessing in disguise as the favourite Sandy Grant ($1.45, David Grant) was squeezed out of the contest before the opening turn was completed.

With the biggest threat in the race now out of the equation Blue Diamonds began to make her charge through the field, working her way to third across the back straight.

She had five lengths to catch up on Hay Pepper and had three between herself and second placed Way It Is ($17, Carl Moss) but she found another level on the bend.

Blue Diamonds worked her way around the outside of Way It Is and continued her charge to chase down Hay Pepper by a head.

The time was 26.95.

"She's bred to get to the 600 and 700. She went to Wenty with no luck and then we gave her an easy start at her last start, then the plan was to come here and hopefully place," Rimmer said.

"She took it out though and now she'll be back next week over the 500m. Then we'll see what happens after that.

"I wasn't too sure about it coming around the back but she's got a big motor and she used it today."