Shaco vs Master Yi

Gank with Deceive (Q) and come in behind your target: Backstab (passive) empowers hits from behind, and your first invisible auto becomes a critical strike.

Save Two-Shiv Poison (E) to finish: the shiv deals much more damage to a target below 30% health.

Cast Hallucinate (R) to bait their spells: you briefly disappear and reappear with a clone, which explodes on death into three boxes that fear.

Place Jack In The Box (W) on their escape routes or at a camp entrance: invisible after a delay, it fears champions who come near, then shoots them.

Against Highlander (R), don't run alone: regroup with your team, because he gains speed and ignores slows.

If you have CC other than a slow, land it right after Alpha Strike (Q): during the strike, he's untargetable, and Highlander (R) ignores slows.

If you have CC, interrupt Meditate (W): he channels it to heal, more at low health, and to reduce the damage he takes.

Put pressure on his jungle early on: Master Yi is strongest once he has his items, and each stolen camp delays him.