Aidan O’Brien suffered an early reverse in his quest for Classic honours when Vodafone Oaks hopeful Chenchikova was beaten on the opening day of the Irish Flat season at the Curragh.

Michael Hills believes Maids Causeway has improved for her second place in the 1000 Guineas but is not sure whether his mount will be able to reverse placings with Virginia Waters at the Curragh on Sunday.