A sphinx named Alhammarret arrives, having heard about the incident. He's a mind mage and a political arbiter. You leave your home to train with Alhammarret, hoping that he can help you control your abilities. He frequently tests your progress.
Alhammarret has many defensive cards and mill cards, as well as four Clash of Wills; he also has two Goliath Sphinx, which outclass any one of Jace's creatures.
The big thing in this matchup is to play around Clash of Wills. The most important spells for Jace to resolve are the creatures that can attack past Alhammarret's blockers, namely Phantom Warrior and Phantasmal Dragon. Try to bait Clash of Wills with unimportant spells if Alhammarret passes with mana up and cards in hand.
There aren't many spells Alhammarret has that should worry you if you've resolved a Phantom Warrior or Phantasmal Dragon. Goliath Sphinx is the only single card Alhammarret has that can deal with a resolved Phantasmal Dragon (he might be able to build up 5 power worth of flying blockers, but that's would take at least three cards without Goliath Sphinx and it's vulnerable to Turn the Tide) and he has no real answer for Phantom Warrior. Still, you should try to leave up three mana for Cancel if possible once you've resolved one of those creatures, except perhaps to play another one to speed up your clock.
Alhammarret doesn't have many real threats in his deck, so you can also try to stall until you can Psychic Spiral his deck away, but it's slower than winning by attacking with Phantasmal Dragon and Phantom Warrior (and you only have one Psychic Spiral anyway).
If he manages to mill a large portion of your deck, another viable strategy is to mill yourself using Divination, then use Mind Spiral, though this is very situational.