The Rock relies on Pernicious Deed to sweep our board and Natural Order to cheat in a huge green creature, so Duress is excellent at stripping either threat, along with Cabal Therapy or removal, before it resolves. Smother answers their early mana creatures like Birds of Paradise and Wall of Blossoms/Wall of Roots cleanly, slowing their ramp into Pernicious Deed or Natural Order. Mulch is cut since it doesn't help us race a grindy deck that out-values us with card advantage; we'd rather have proactive disruption. Keep Wasteland in to pressure their Llanowar Wastes manabase, and be mindful that Pernicious Deed can wipe our board, so sequencing Terravore and Devastating Dreams around it matters.