WUR is a Jeskai-colors control deck very similar to matchup 1, leaning on Firebending Lesson, Combustion Technique, and Jeskai Revelation, so Flashfreeze counters their entire red suite at great value and Disdainful Stroke answers Jeskai Revelation (MV7) or Thor, God of Thunder (MV5). Avatar's Wrath is weak here since it's mostly dead once their board is empty and they hold up countermagic like Negate and Spell Pierce to protect their own plays. Stoic Sphinx is a hard-to-interact-with flash threat that dodges their sorcery-speed removal like Avengers Disassembled, and its hexproof-until-you-cast-a-spell clause keeps it safe from Combustion Technique on turns where you haven't cast a spell.