I've been playing this deck in Best of 1 for the last 2.5 weeks of March, and have experienced a positive winrate with it over the course of over 100 games.  (approx 60% winrate)

Survive.  Remove their creatures.  Gain life, draw cards.

(1) Play Dovin's Acuity and instants for value.  If you have the choice to recast Acuity and don't need the 2 life right away and don't have an instant immediately available to play, don't recast, especially if you suspect Mortify.

(2) Don't let Teferi resolve and stick.  I can't stress this enough.  It's an easy thing to deal with, so don't get caught out by it.  This card is super difficult to deal with if it sticks around even one turn.  Mastermind's Acquisition for Sorcerous Spyglass is always an option, but it's piss-poor.  Avoid that if possible.

(3) Figure out what they are doing.  If it's Burn, sandbag a Mortify to deal with Experimental Frenzy.  Gain a bunch of life.  If it's creature-based aggro, dig for removal and sweepers and Mission Briefing.  The first Acquisition can get a sweeper.  One toughness aggro, get your Ethereal Absolution.  Other stuff, figure out their wincons.  Unmoored Ego that stuff.  Clear the Mind to shuffle our deck back.  That usually gets the concession.  You can win any matchup on a long enough timeline: you have inevitability.

(1) Naturally mill them out or show them you can shuffle back with Clear the Mind (of which there are two in the sideboard) after a couple Unmoored Ego.

(2) Get one of your other wincons.  My favorite is Ethereal Absolution vs aggro, Mnemonic Betray vs a lot of other things.  I've fetched out other stuff only a handful of times.  

Don't forget that searching your own library is an option in the deck.  The first Mastermind's Acquisition may be for Kaya's Wrath or Mortify or Sorcerous Spyglass.  Spyglass on Azcanta, the Sunken Ruin or Treasure Map/Cove is 100% legitimate.  Do it.  You have The Immortal Sun in the Sideboard to handle pesky Planeswalkers.  

Honestly, the percentage of games where people just scoop to Unmoored Ego + Clear the Mind is probably in the 50%+ range.