He's made several adjustments - in his first couple of wins he was serve & volleying a ton, going for the short angles to get Med out of his comfort zone, and overall just forcing himself to up the aggression to the max. But as Sinner always says, it's a constant chess game, made of adjustments and counter-adjustments. In this match, for example, I got the impression he was purposefully rallying hard down the middle a lot, just trying to take away the angles, and probably feeling like he had the edge as far as pure pace and solidity from the back (which he obviously did).
Then, of course, Sinner's game has just overall grown in every area of the game, starting from the serve.
Still, I continue to feel the mental component is paramount, and once that psychological dynamic started to shift, it was always gonna be tough for Med. In fact, I just heard Sinner's interview on Italian TV, and he stressed how he really wanted to start strong in both sets. That to me validates what I was saying above - i.e.he knows that he is now in Med's head and that it will all be downhill if he can just step onto his throat right away.