O'Brien will be back better after bruising experience at chaotic Kentucky Derby

When the gonzo journalist Hunter S Thompson descended on the Kentucky Derby in 1970 he described Churchill Downs as resembling a "huge outdoor loony bin" and while plenty else has changed in the past 48 years, the atmosphere at America's most famous race palpably hasn't.

Aidan O'Brien could have been channelling Thompson when he described the scenes that greeted him, Ryan Moore and Mendelssohn last Saturday, when their 'Run For The Roses' ended in a deflating last-place finish at a half-drowned Churchill Downs.

"There were nearly 160,000 people there, all wet, all screaming, the rain coming from everywhere," O'Brien recounted to the Racing Post, possibly fixing a Marlboro into the end of a cigarette holder. "Everyone was jammed in and everyone had these plastic things on them. I cannot explain it to you. There were people everywhere. Mendelssohn was just mind-blown by the whole thing."