Owner-breeder Yvette Pearce ticked off a bucket-list item when buying a Zabeel mare and against expectations she has produced a Group One-winning two-year-old.

A stunned Pearce was not in the minority at Randwick as El Dorado Dreaming unleashed a giant-killing burst down the outside to nail Golden Slipper runner-up Oohood in the $1 million Sires' Produce Stakes (1400m).

The Ben Smith-trained filly snuck home as a $81 outsider, the longest odds for a Sydney Group One winner since $101 shot Zavite claimed the Ranvet Stakes in 2011.

Pearce snapped up Solanas when she was in foal for $35,000, hoping the progeny would develop into a viable three-year-old.

"A Zabeel mare was on my bucket list and the thinking was to breed a three-year-old 1600-metre horse," she laughed.

Pearce had to be convinced to start El Dorado Dreaming on a seven-day back-up from a second in a Newcastle maiden but Smith talked her around.

"I thought, 'Are you sure about this? I don't want to over faze her'. He said, 'I know the horse'."

Admittedly, Smith did not expect El Dorado Dreaming to secure his second Group One in a fortnight after In Her Time's victory in The Galaxy.

"We weren't just here to make up the numbers but we didn't expect her to win," he said.

El Dorado Dreaming, who had just $9755 in prize money before she broke her maiden in remarkable fashion, started her career in Tamworth in October.

"We were looking to tip her out and that was one of the first two-year-old races of the season," Smith said.

"We didn't think she'd be a two-year-old but she just trialled so well in February. She's come back a lot better and now she's a Group One winner."

Oohood, the $3.20 favourite, looked on course to improve on her Golden Slipper disappointment but was pipped by half a head.

Outrageous, a $61 roughie, was a length back third.

The Group One Champagne Stakes (1600m) is the usual progression from the Sires' and Smith would not rule it out.

"The way she run today I'm sure she'll be up to it and she won't be a hundred to one."

Smith paid credit to jockey Damian Lane, who rode El Dorado Dreaming for the first time, while Zac Purton was left to lament another near miss for maiden-seeking Oohood after Estijaab claimed the Golden Slipper by a long head.

"She burst through like she had the race won but then just seemed to pull up," he said.