Mardu Energy pressures you with efficient one-drops and threatens to steal resources with Ragavan, Nimble Pilferer, so Fatal Push comes in to answer their key threats cleanly before they generate too much value. Thoughtseize is essential to strip removal spells and disruptive pieces — particularly Goblin Bombardment, which is your biggest concern since it lets them sacrifice creatures in response to undying triggers, completely blanking your combo. Force of Vigor destroys Goblin Bombardment (an enchantment) and can hit any Wear // Tear targets they leave up, two-for-one-ing them for free. Trim the slower card advantage sorceries and non-combo creatures to make room; Orcish Bowmasters stays because it cleanly punishes Ragavan and creates a blocker. Post-board you want to lead with disruption and tutor up Yawgmoth only once you've neutralized their sacrifice outlet.