Tron relies heavily on artifacts like Bonder's Ornament, Expedition Map, Barrels of Blasting Jelly, and Giant's Boulder for mana fixing and ramp, all of which Annul can counter on the spell. Spell Pierce is weak here since Tron often has excess mana available to pay the {2} tax, so swap it for Annul which flatly denies their key artifact-based mana engine. Keep your Counterspell and removal suite intact to handle their large creatures like Bramble Wurm and Nyxborn Hydra, and race with Tolarian Terror before they assemble the full Tron land base.