This mirror is won by whoever assembles the Guttersnipe/Kessig Flamebreather damage engine first and races most efficiently, so avoid diluting the core with slow card-advantage pieces. Relic of Progenitus comes in to strip the opponent's graveyard of Faithless Looting and Lava Dart before they can flash them back, denying extra card selection and reach in a race, while still cracking for a card when needed. Pyroblast and Red Elemental Blast stay in the sideboard, as this mirror gives them little to do. Trim the slower Sazacap's Brew and one Highway Robbery since this matchup rewards low-to-the-ground speed over incremental card draw.