The leading Irish rider suffered a major blow in the summer after losing the job as number one rider to Gigginstown House Stud, for whom he won the Cheltenham Gold Cup with Don Cossack in 2016.
Though Cooper insists he will continue to be based on home soil, he may well be seen in the UK more often, with opportunities in Ireland having been thin on the ground.
And he went close to making a winning start on Guiding Stars, but the Harry Whittington-trained four-year-old found odds-on shot Hatcher too good in the bumper at Worcester.
Cooper sent Guiding Stars (7-1) into the lead just under two furlongs out but the move was covered by Harry Skelton on Hatcher, trained by his brother Dan.
The 8-13 favourite asserted in the closing stages and went on to score by a length and a quarter.
The two protagonists pulled nine lengths clear of Shadow's Girl in third.