Popular grey Alpinista hit the heights on home soil as she toughed it out in the Darley Yorkshire Oaks.
The 7-4 favourite's first success at the highest level was achieved by a length from Aidan O'Brien's filly Tuesday.
Given a positive ride by Luke Morris, Alpinista answered every call and found extra to deny the runner-up another major prize. Adding to her Group 1 achievements in Europe, the winner is now 7-1 with William Hill for the Arc.
La Petite Coco followed fellow Irish raider Tuesday home to fill out the places.
Alpinista's trainer Sir Mark Prescott, celebrating his first British Group 1 in five years, said: "These are hard to come by for a smallish stable, every five or six years we'll have a good one come along and it's tremendous when it happens."
Full results from Ladies Day at York's Sky Bet Ebor Festival
1.50
1 Swingalong 25-1
2 Queen Me 20-1
3 Matilda Picotte 11-1
2.25
1 Shouldvebeenaring 5-2f
2 Washington Heights 8-1
3 Northcliff 66-1
3.00
1 Blue For You 11-2f
2 Escobar 28-1
3 Tyrrhenian Sea 10-1
4 Orbaan 14-1
3.35
1 Alpinista 7-4f
2 Tuesday 7-2
3 La Petite Coco 4-1
4.10
1 Haskoy 13-2
2 Time Lock 6-1
3 Judith 14-1
4.45
1 Kyeema 8-1
2 Indian Dream 11-2
3 Courageous Knight 5-1
5.20
1 Adaay In Asia 11-1
2 No Nay Nicki 25-1
3 Sound Of Iona 40-1
