Master Yi vs Sett

Cast Alpha Strike (Q) to dodge a spell or a burst: you're untargetable during the strike, and your autos lower its cooldown.

Cast Meditate (W) to tank a burst mid-teamfight: you take less damage, heal more at low health, and the time left on Highlander (R) is paused.

Activate Highlander (R) to chase: you gain move speed and attack speed, and slows no longer affect you.

Chain kills in teamfights: each takedown lowers the remaining cooldown of your basic spells, and extends Highlander (R) if it's active.

Get out of the center of Haymaker (W): it deals true damage there, and the sides only deal physical damage.

Keep your distance once Knuckle Down (Q) is used: he has no dash, and it's this spell that speeds him toward you.

Don't take a big trade unless you can finish it: Haymaker (W) stores part of the damage he takes as Grit, for a stronger shield and punch.

Don't stay grouped behind your tank: The Show Stopper (R) can slam them onto you, and the damage depends on their bonus health.