Jax vs Kennen

Start your trades with Counter Strike (E): you dodge autos and take less area damage, and each dodged auto adds damage to the stunning counterattack.

Look for long trades: each consecutive auto increases your attack speed thanks to Relentless Assault (passive).

To escape, place a ward and jump to it with Leap Strike (Q): it can target any unit or ward, allied or enemy.

Activate Grandmaster-at-Arms (R) up close: it only grants armor and magic resist if it hits a champion, and your bonus hits then land every other auto.

Dodge Thundering Shuriken (Q): each spell that hits you applies Mark of the Storm (passive), and on the third, you're stunned.

Back off as soon as he rushes at you with Lightning Rush (E): it's his engage, often followed by Slicing Maelstrom (R).

When he has Slicing Maelstrom (R), spread out from your allies: the storm hits every enemy around him, and its repeated hits end up stunning.

Wait for Slicing Maelstrom (R) to end before you fight back: during the storm, he gains armor and magic resist, then the spell has a 120-second cooldown.