Tom Marquand, who has enjoyed several successful riding stints in Australia, has won his first classic race in England aboard Galileo Chrome.
The Joseph O'Brien-trained colt was a late pick-up ride for Marquand after regular jockey Shane Crosse became unavailable because of a positive test for Covid-19.
With Crosse forced to isolate in Ireland, Marquand replaced him aboard Galileo Chrome in the St Leger at Doncaster and prevailed by a neck over Berkshire Rocco.
Marquand was thrilled to land the feature win for O'Brien but said he felt for Crosse.
"It's terrible for him - but my God, how the racing game is a leveller," Marquand told ITV Racing.
"The last couple of weeks have felt hard and to pick up a spare ride like this in a British classic, for Joseph O'Brien of all people, is incredible."
Marqaund enjoyed a ground-breaking riding stint in Sydney earlier this year when he won the Group One Queen Elizabeth Stakes aboard Addeybb and the Group Three Manion Cup on Young Rascal.
In a big weekend of European racing, top mare Magical got the better of Ghaiyyath in a thrilling finish to the Irish Champion Stakes at Leopardstown.
Trained by Aidan O'Brien and ridden by Seamie Heffernan, the five-year-old bounced back from her defeat in the Juddmonte International to take out the feature.