Sated Yi vs Sated Jax

Jax can easily win a 1v1. Even if Jax didn't E or anything, he's tankier and still gets the BotRK and ult procs. He'd do just as much damage and be tankier, plus have just as much lifesteal unless Yi built a BT. If he did build a BT then I don't know.

Probably Jax unless Yi dodges the stun and doesn't get hit while Jax is using counter strike

Sated Yi, his kit has far more on hits as well as being able to meditate Jax while he is counterstriking then alpha striking right before counter strike goes off, then proceeding to melt him instantly.

yi

kit wise, Yi would probably win, but Jax has outplay potential

skill matchup. However Yi synergizes with lifesteal/crit better and can dodge counterstrike.

Yi has an auto dependent kit, Jax's E can negate quite a bit of damage and also cancel Yi's meditate, while dealing out considerable damage to him. Jax tends to be tankier as well, especially with his ult. Jax is actually considered a counter to sated junglers.

Skill matchup and mind games. Jax can reactivate the stun early or late and Yi has to predict it to dodge it. If Yi dodges it, he beats Jax. If not, Jax deals enough damage during the time Yi is stunned to be able to win.

Also Sated Yi does extreme damage when his E is on. If Jax starts counterstrike when Yi uses E, to be able to ignore most of the true damage, he could win even if Yi dodges stun.