Master Yi vs Bel'Veth

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.

Back off when she takes her true form with Endless Banquet (R): she gains health, range and attack speed, and with enough stacks, the form lasts until she dies.

Dodge Above and Below (W): if it hits you, you take a knock-up and her Void Surge (Q) in your direction is refreshed instantly.

If you're the lowest-health enemy near her, get out of Royal Maelstrom (E) range: every slash targets you, and she gains lifesteal and damage reduction.

Deny her large monsters and kills: Death in Lavender (passive) gives her permanent attack speed for each one.