Now, I can’t confirm the story for sure, but my understanding from what I heard after the game is that he actually had a Raffine, Scheming Seer in hand that he could have cast before attacking, but instead he opted for the post-combat Kaito line, which didn’t work because of his own Thalia.
Once the Kaito play was reversed by the judge, I think he should have still cast Raffine in the second main-phase if he had one, but he opted to pass the turn instead. At the time, this made me think he had a Spell Pierce in hand.
On my turn, I drew an Abrade, played my third land, and passed the turn. Now I felt like I was in an okay position, as I could counter whatever his next play was, or Abrade his Thalia (baiting out the possible Spell Pierce to resolve Fable) if he chooses to pass the turn again without casting anything.
On his fourth turn, he once again attacked with Thalia and then tried to resolve the Kaito, but this time I could counter it. I then untapped, played my fourth land, and resolved a Fable of the Mirror-Breaker.
The board was now fairly even – he had a Thalia in play and I had a Goblin token and a Fable of the Mirror-Breaker. However, my hand was just lands and an Abrade, while I felt that he must have had some good cards in his. On his fifth turn, he spent a lot of time thinking, before attacking with Thalia and passing the turn without playing a fifth land.
This made me think of two things – either he was debating whether to play Raffine and try to draw a land with connive to hold up Spell Pierce through his Thalia, or he drew an Ertai Resurrected. Personally, I think if he had the Raffine, he should have just played it, but nonetheless, this was the line he took.