Sioux Nation completes O'Brien treble in Lacken Stakes Aidan O'Brien and Ryan Moore completed a treble on a reduced card (final two races cancelled) at Naas as Sioux Nation returned to his best when defying a Group 1 penalty in the Goffs Lacken Stakes. Winner of last season’s Phoenix Stakes, the Scat Daddy colt displayed his class to dismiss the opposition in this Group 3 contest. The uneasy 15/8 favourite showed he had come on from his reappearance at Navan last month by leading a furlong out under Ryan Moore to score by a length and a quarter from stable companion Fleet Review. Moore and O’Brien were successful earlier on the card with Broadway and Sergei Prokofiev. Sioux Nation won the Coventry Stakes at Royal Ascot in 2017 and could return there next month for the Commonwealth Cup or the King’s Stand Stakes. O’Brien said: “We came here to find out if it was five or six furlongs at Ascot. “Seamus (Heffernan on Fleet Review) let his lad roll along to make it a good, strong six because we always felt he had a lot of speed and wanted to know whether we would go for the King’s Stand or the Commonwealth Cup. “Ryan said he has all the speed in the world and he would have no problem going back to five, but maybe let him take on the three-year-olds this year (Commonwealth Cup). He also said he would be looking forward to the Nunthorpe. ‘He’s a great traveller and he quickens. It couldn’t be fast enough for him. Fast ground and fast horse — that is usually the way.” Paddy Power cut Sioux Nation into 7/1 (from 10/1) for the Commonwealth Cup. The final two races were cancelled in the interest of safety. Light rain during the day resulted in a slippery surface on the bend into the home straight, and a number of riders expressed their concern after the first race.