Iapetus is Weary, which gives him -1 on all actions. That would be 8 attack and 13 defense for the Tytalus challenger!
Lucia is fresh, and has a 22 on attack and a 10 on defense.
Iapetus' attack is insufficient to penetrate Lucia's defense: as his phantasm lunges forward, it blows clear of Lucia's, and loses its shape temporarily as, instead of turning back to face the other phantasm, it merely re-forms facing the other direction.
Lucia's phantom surges towards the other, for a solid attack (11 weakening - 7 resistance = 4), knocking Iapetus' little ghost-construct back a bit. Iapetus is now Tired (-3 to all actions). The crowd boos and jeers ever more loudly.
Iapetus realizes that Lucia has been putting her best art into Attack and that her Defenses have been relatively weak-- just not quite as weak as his offense. This ain't his first rodeo, and he knows that very attractive, charismatic magi tend to have a natural aptitude for gaining the advantage (attack is +Pre), while very sharp, shrewd magi are good with defense (def is +Per); incredibly intelligent magi do more damage with only a small amount of advantage (weakening is +int) and very healthy magi are most resistant to taking damage (+Sta).
He then sizes up his opponent-- she is incredibly beautiful and has a way of moving that is simply entrancing; the only person he's ever met who was Lucia's equal in charisma is Isabelle d'Arras (they both have +5 Presence). Her build is rather slight, though; if she tried to run a mile she'd probably collapse in exhaustion before she got very far. And Jerbiton are known for selecting Gently Gifted apprentices, regardless of their intelligence; the house has a reputation for their wizards being not-so-smart compared to the rest of the order. (Most magi look for at least a +3 intelligence in anyone they're going to train; Jerbitons are thrilled if they find a Gently Gifted kid whose intelligence is non-negative.) Long story short, Iapetus has reasoned out that he would fare much better if he attacked with Muto and defended with Mentem.
Before Iapetus can adjust his strategy, the angry mob of faeries reaches its flashpoint, and surges forward. One walrus spits a stream of saltwater in Lucia's face, while a mermaid yanks the little maga by the hair, and a Spanish pirate grabs at her, tearing the sleeve off her dress. Lucia's phantasm pops out of existence as the maga loses concentration, leaving Iapetus the victor.