In actuality, their battle against the Necromancer began the moment they saw the Mage Tower. Herrera lived up to her name as Anthony's prized disciple. Although she was only one level higher than Link, her battle experience from nearly 20 years of magic research was not something Link could hope to match up to at this point. This was clear from the way Herrera fought.
The thick white mist was making it difficult to determine the exact location of their enemies. While Link was blindly casting his spells, Herrera decided to cast a Level-2 True Sight spell to dispel the mist. What Link had often thought of as superfluous spells were actually useful in certain situations and the ability to maximize their potential was something he still had to learn.
Bryant once said, "There are no useless spells, only useless Magicians." Link could not agree more.