Marsha has become the highest-priced horse sold at a European auction, fetching six million guineas ($A 11 million approx) at the Tattersalls December Mare Sale.

The Prix de l'Abbaye and Nunthorpe winner, trained by Sir Mark Prescott, was bought by MV Magnier, son of Coolmore Stud's John Magnier, for a new partnership.

Magnier had the final bid for the four-year-old after a head-to-head battle with John Gosden, who was bidding for Godolphin.

"She really is something special," Magnier said.

"Sir Mark has done a great job with her, she was very fast and the lads were very keen to have her. She is the best sprinter of the year and she will go to Galileo."

For Dan Downie, racing manager of vendors Elite Racing Club, it was the end of long day.

"We did have a price at which we would have taken her home, but we did think it was going to be unlikely," he said.

"The funds will help with ongoing and long-term running of the Club, but we will, of course, take a look at our nomination plans, in particular for Marsha's dam, Marlinka."

Godolphin managed to secure Grade One winner Zhukova for 3.7 million guineas.

The Man O'War Stakes winner, who was trained in Ireland by Dermot Weld, was bought for Sheikh Mohammed's operation by Anthony Stroud.