Tryndamere vs Jax

Keep your Fury high before a trade: with Battle Fury (passive), it raises your critical strike chance. Spend it with Bloodlust (Q) when you need health.

Cast Mocking Shout (W) before a trade against a physical damage champion: it lowers their attack damage, and slows enemies who turn their back on you.

Count on Spinning Slash (E) to stick to your target or to escape: each critical strike lowers its cooldown, more so on a champion.

Wait until you're close to death to cast Undying Rage (R): you can't die during the effect, and delaying it pushes the enemy to take risks to kill you.

Split push in a distant lane to draw several enemies: Undying Rage (R) helps you hold them off while your team takes an objective.

Take a short trade, then back off: Relentless Assault (passive) increases his attack speed with each consecutive auto.

During Counter Strike (E), back off instead of attacking: he dodges your autos, then stuns nearby enemies, dealing more damage per dodged auto.

Trade right after Counter Strike (E): it's both his defense and his only stun, and it has a 17 to 9 second cooldown.

In the late game, don't leave his split push unanswered: send someone to hold his lane, or force an objective on the other side of the map.