Just how?

Edit: Can you guys please read the title. I clearly said 1v1, that means no interuption, no ganking and all that sht.

With CC

You don't. You make sure you don't die to him inlane, and let everyone know when he's MIA.

MR

cc and ignite = a dead yi

You cant beat him

play leblanc, udyr, pretty much anyone with a stun or a heal debuff

Good thing this is a team game.

CC
Heal reduc
Trading potential

After his Q, he really has no way of damaging you unless you're stupid enough to let him get into melee range. When I play AP yi and my Q chunks them for quite a bit, they for some reason decide to wait back instead of taking the oppurtunity to attack while i'm weak. And by the time they come back in, it's already off CD.

Any good single target burst champ ruins AP Yi. Leblanc for example just waits until he Q's then dashes forward and burst him down. If he heals so what? Thats cs he missed then just do it again.

I think a lot of inexperienced members (including ymself sometimes) forgets to kinda stay away from the minion line so that Yi's Q doesn't hit them.