Ethical Diamond will attempt to defend his Longines Breeders' Cup Turf title at Keeneland on Saturday

Following a historic triumph at Del Mar a year ago, Willie Mullins returns to the Breeders' Cup, this time at Keeneland, with Ethical Diamond chasing further American success.

The six-year-old produced a stunning late surge under Dylan Browne McMonagle to defeat Rebel's Romance, delivering the National Hunt maestro a landmark maiden victory at the prestigious year-end championships.

With his entire campaign tailored around another Stateside assault, he'll now bid to retain his Longines Breeders' Cup Turf crown on Saturday.

"I think it's a much more competitive race this year, but I think we have trained for it while a lot of the others have had a busy autumn," Mullins explained.

"I just had a look at him and he is in great shape. He's been doing everything well, going into the stalls and drinking well.

"He's drawn one which means different tactics and we might have to jump and go, but we will leave that to Dylan. He's more mature this year and easier to ride while he settles better."

Ethical Diamond finished runner-up to Sir Mark Prescott's reopposing Tiffany on his most recent outing, though Mullins remains undaunted, noting: "He got into a lot of traffic problems at Kentucky Downs, but we are here. I never dreamed I'd have one good enough to run at the Breeders' Cup with the type of horses we have."