This matchup is a race against a fast, damage-based combo-aggro deck, so maximize cheap interaction that answers their red spells and creatures directly. Blue Elemental Blast and Hydroblast can counter or destroy key threats like Guttersnipe and Kessig Flamebreather, or counter burn spells like Fiery Temper and Lightning Bolt outright. Cut slower card-selection pieces like Abandon Attachments, Spell Pierce (too easy to play around when they're tapped out on cheap spells), and Plunder the Trollshaws since they don't affect the board fast enough. Keep Snuff Out and Counterspell as premium answers to their threats.