False Swipe / Sleep Status are your primary options. Sleep is the strongest status condition along with Frozen, but Frozen is like impossible to induce. So yeah, put it to sleep and False Swipe it down to a guaranteed 1HP. I suggest using Crobat because it learns Hypnosis and Mean Look, while having a speed that is greater than that of Suicune's. Wobbuffet leads also help trap it.