Kesampour kept all-comers at bay to land a narrow victory in the Prix Greffulhe at Saint-Cloud.
Expected to maintain his perfect record with some degree of ease, the Mikel Delzangles-trained colt looked like being swamped at one stage, but repeatedly pulled out more as the field finished in a heap.
The Group Two event was won 12 months ago by Pour Moi on his way to glory in the Investec Derby.
