Godolphin has outlasted Coolmore in a bidding duel at the Tattersalls sale to secure the highest-priced yearling sold at auction this year, paying 4 million guineas ($A 6.745 million abt) for a daughter of champion European sire Galileo out of American Group One winner Dank.

As the price continued to rise, it was Coolmore's MV Magnier and John Gosden on behalf of Sheikh Mohammed who went head to head in pursuit of the filly.

Not since 2013, when Al Naamah fetched 5,000,000gns, has a yearling filly gone for as much.

"She is from a proper owner-breeder and was clearly an obvious one to go for, and obviously lots of people wanted her;" Gosden said.

"Fillies do have both racing and breeding options.

"She is an outstanding filly and to produce one like her, particularly a first foal, is an incredible achievement. It is not easy to do."

The filly, to be named Gloam, was bred by James Wigan.

"We've known throughout the year that she is a particularly nice filly," he said.

"She has a great character. She's always been a star.

"She has a lot of the mare about her. Hopefully she has a bit of Galileo about her and I think she is a good combination of the two, actually."