Turn 3 Lone Champion (they have to kill righteous and usually also kill Keleseth so you'll have no board that turn so Lone Champion is buffed. Otherwise trade with Kele and play Lone)
Turn 4 Saronite (or if you have drawn a buffed taunt with more value like 4/4 Corpsetaker etc.
General plan: Buff life-steal minions, keep playing taunt. Always assume they have Leeroy.