Sett vs Yasuo

Start your trades with Knuckle Down (Q): you rush toward your target, and your next two autos deal bonus damage based on their max health.

Cast Haymaker (W) right after taking damage: the stored Grit gives you a shield and extra damage, dealt as true damage in the center of the punch.

Don't back too early at low health: Pit Grit (passive) increases your health regen based on your missing health.

Stand between two enemies before Facebreaker (E): grabbed from both sides, they're stunned, otherwise only slowed.

Grab their tank with The Show Stopper (R) and slam them onto their carries: the damage around the impact depends on the bonus health of the target you grab.

Hit him with a cheap attack to trigger the Way of the Wanderer (passive) shield, then start the real trade: otherwise, it absorbs your best damage.

If you have projectiles, save them for after Wind Wall (W): it blocks them all for 4 seconds, on a 25 to 17 second cooldown. Other spells go through it.

Don't stand right behind your minions: each one gives him a target for Sweeping Blade (E), and he gets closer to you with every dash.

Get out of the line of his whirlwind, the third Steel Tempest (Q): without a knock-up, he can't cast Last Breath (R).

Judge his threat by his crit items more than his level: Way of the Wanderer (passive) raises his critical strike chance, so each crit item does more for him.