Veteran jockey Kerwin Clark has celebrated his biggest career win aboard Lovely Maria in the Kentucky Oaks at Churchill Downs.

The filly burst past Angela Renee in the final furlong (200m) for a 2-3/4-length victory that left the 56-year-old jockey fighting back tears.

"I've been riding for 40 years and won my first Grade One last month at Keeneland with this horse," Clark said .

"Then we won this race today. I am very blessed. Blessed to have this horse, blessed to have trainer Larry Jones in my life and believing in me and to have owner Brereton Jones believe in me and stick with me."

Making it doubly sweet for Larry Jones was having his other horse, I'm a Chatterbox, finish third.

Larry Jones and Brereton Jones, who are not related, have now won the Oaks three times together.

A crowd of 123,763 was at Churchill Downs on Friday (Saturday AEST).