Aidan O'Brien served notice on Sunday that his Ballydoyle stable is firing on all cylinders as his Mount Nelson upset the heavily favored Spirit One in the $320,000 Criterium International at Saint-Cloud. Mount Nelson corralled the pacesetting Spirit One at the eighth pole and held on gamely under Jamie Heffernan to prevail by a head. O'Brien also trains the third-place finisher, Yellowstone. Coupled with Yellowstone, Mount Nelson started at 10.90-1 and covered the mile on good to soft ground in 1:41.30.