The pair have almost identical records, having been beaten on their respective debuts before winning their next two starts, most recently at Group Two level.
Benvenuto Cellini, by Frankel and out of a Breeders’ Cup winner in Newspaperofrecord, shot to the head of the Derby betting after winning the Champions Juvenile Stakes by five lengths at Leopardstown.
Hawk Mountain, a Wootton Bassett colt out of the dual Group One winner Hydrangea, was last seen impressing in the Beresford Stakes, which has been such a good guide to this race down the years.
Earlier in the week Benvenuto Cellini was a long odds-on favourite, but plenty of support has come for Hawk Mountain in the interim.
O’Brien’s third runner in a six-strong field is Action, third in the Royal Lodge at Newmarket four weeks ago, while both Andrew Balding’s Item and John and Thady Gosden’s Oxagon have been declared in the hope the ground dries up.
Adrian Keatley’s Rochfortbridge completes the sextet, having finished second in the Listed Silver Tankard Stakes at Pontefract on Monday.