From a seemingly impossible position on the home turn to a similarly improbable proposition at the 200 metres, top-class filly Guelph has somehow snatched a last-ditch victory in Saturday's Group One Champagne Stakes (1600m) at Randwick.

On an afternoon when short-priced favourites It's A Dundeel and Toydini had their colours lowered, Guelph looked set to follow suite when she was shuffled well back in a strung-out field.

Even trainer Peter Snowden had given up on her when leader Fuerza skipped away and kicked strongly.

"We had intended to be in the first half a dozen and she got a mile back," Snowden said.

"I thought it was too much to do, especially when the leader kicked and it was just going to be a sprint home for the last 600 metres.

"She started to tack up well to the furlong, but I thought she had too much more to do. But she was good enough to do it."

Guelph's victory added a bright spot to an otherwise difficult week for Darley's Sheikh Mohammed.

His Godolphin operation has been rocked by an eight-year ban handed down to one of its English trainers, Mahmood al-Zarooni, for administering horses with anabolic steroids.

It also cemented Guelph as one of the best of her generation after she finished a fine fourth in the Golden Slipper and produced a powerhouse performance to win the Sires' Produce Stakes.

Snowden said Guelph had done an outstanding job to cope with a Blue Diamond campaign and the rigours of the Sydney two-year-old triple crown.

"What she's done shows what she's made of," he said.

"It's testament to her ability and her toughness and she's right up there with the best of them this season."

Guelph ($2.50 fav) arrived in the final stride to beat Fuerza ($26) by the barest possible margin of a nose, foiling what was a brilliant tactical ride by Jim Cassidy on the runner-up.

"I tried something different and I nearly pulled it off," Cassidy said.

In a close finish, Equator ($20) was another short neck away third.

Darley has now won three of the past four runnings of the Champagne Stakes following victories by Skilled (2010) and Helmet (2011).