Master Yi vs Irelia

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.

Don't stand near your low-health minions: Bladesurge (Q) resets when it kills, so she chains dashes from minion to minion until she reaches you.

As soon as the first blade of Flawless Duet (E) lands, change direction: the stun only hits enemies caught between the two blades.

Take your trades when Ionian Fervor (passive) isn't stacked: she builds stacks with her abilities, and at max stacks her autos deal more damage.

Save your burst for after Defiant Dance (W): while charging, she takes much less damage, but she can't do anything else.

Dodge Vanguard's Edge (R): its blades make you Unsteady, which resets Bladesurge (Q) on you, and the cage they form damages and slows anyone who crosses it.