Hearthpwn

Here's the deck I used to beat Patchwerk:

Some basics of the fight:
-Patchwerk will only ever attack with his weapon, that is a Windfury Hook 4/8 with Deathrattle: Return to hand.
-His Hero Power costs 4 mana and will destroy a minion.
-He does not have any other cards, and he will not draw any causing fatigue unless forced to through deathrattle effects and/or Oracle-
-He is going first, being the only boss so far to not hold the coin.

Tactics are pretty simple, you need to mulligan for Ooze and Mind Vision in opening hand, else you lose.

T1: Coin+Ooze
T2: Mind Vision+ 1 mana taunt/Voodoo
T3: Hook
T4+: Stay alive and kill him

Most of the time, this will be over by turn 6-7, so the Holy Fires are likely not needed. Once you got him around turn 4+ you want to always keep 2 minions with taunt on board, so that you can block 4 dmg and most likely live to kill him.

If you don't get Ooze+Vision in opening hand, just hit concede. Every turn you block 4 dmg from his weapon is a succesful turn. Other than that, not much more to say.