This matchup is decided by protecting your own threats from Stifle/counters and racing before Phyrexian Dreadnought connects twice; while Warmth is dead against a deck with no red spells, Naturalize destroys Phyrexian Dreadnought since it is an artifact creature. Naturalize also answers Powder Keg, whereas Tranquil Domain has no legal targets because they run no enchantments. Focus on Swords to Plowshares to exile the Dreadnought before it attacks and use Survival of the Fittest to find Ravenous Baloth or Deranged Hermit for board presence. Keep the plan minimal since almost nothing in the sideboard is well-positioned here.