Mono-Blue Stiflenought wins by using Stifle to counter Phyrexian Dreadnought's triggered ability, then countering your threats with Counterspell, Foil, and Gush-fueled permission. Your game plan is to deploy Goblin Lackey on turn one and ride early pressure before their counter suite comes online — Goblin Warchief and Goblin Piledriver through a Lackey hit can close games before they stabilize. Pyroblast and Red Elemental Blast come in as cheap, resilient answers to counter their counterspells and permanently answer Phyrexian Dreadnought if it ever resolves without Stifle protection. Naturalize and Goblin Tinkerer have minimal targets in their mainboard (only Powder Keg), making them dead weight in this matchup where every card slot matters against a reactive blue deck.