Review leopardstown 7th May Aidan O'Brien's trio all finished as one in the Derrinstown Stud Derby Trial at Leopardstown, with Douglas Macarthur just holding off stablemates Yucatan and Capri.Emmet McNamara had the 7-1 winner at the head of affairs from the outset, but looked a sitting duck as Capri and then Yucatan launched their challenges.Douglas Macarthur found plenty when asked, though, eventually prevailing by a diminishing margin of a head from Yucatan, with Capri a short head back in third.O'Brien bagged a double when daughter Ana drove Belgravia (5-2 favourite) to victory in the Crew Of R116 Memorial And Irish Coastguard Maiden.Bean Feasa broke her maiden tag in Group Three company, landing the Derrinstown Stud 1,000 Guineas Trial.Jim Bolger's 10-3 favourite was beaten in a Gowran maiden a week ago, but surpassed that effort with ease, picking up the front-running Asking to win by two and three-quarter lengths under Kevin Manning.Custom Cut produced a battling display from the front to land the Ard Glen Construction Amethyst Stakes.Daniel Tudhope was happy to lead on David O'Meara's 9-2 chance and he just kept finding more, eventually repelling Raymonda by half a length.Brother Bear made a winning debut for Jessie Harrington when taking the Irish Stallion Farms EBF Maiden.Favourite Sioux Nation led entering the final furlong, but Colm O'Donoghue had all moves covered on the 9-1 chance and swept past before scoring by two lengths.Pincheck made it a double for Harrington and O'Donoghue with victory in the Mortons Coaches Maiden.The well-backed 3-1 chance looked short of room entering the final furlong, but got out of trouble in time and ran on well to beat Captain Hardship by a neck.Shane Foley's well-judged ride got Damian English's Geological (20-1) home in the John Fitzpatrick Agricultural Contractor Handicap, while the Fitzpatrick Gallgher McEvoy Solicitors Handicap went to Sheila Lavery's Mandamus (7-1) under Leigh Roche.