Rachael Blackmore and Henry de Bromhead were at a loss to to explain what went wrong during A Plus Tard's defence of his Betfair Chase crown at Haydock.
The Waterford trainer described the performance of the Gold Cup hero as “too bad to be true”.
The Cheveley Park Stud-owned eight-year-old was imperious in winning on Merseyside 12 months ago, sauntering 22 lengths clear under Rachael Blackmore.