Both have exceeded my expectations.
I'm not going to pretend I'm a Sensi expert but in the handful of matches I saw of him previously, I didn't expect him to pose this much of an attacking threat, and more importantly, so reliably. His ball retention skills and game sense have always been visible and he ran circles around our midfield playing almost as a DM for Sassuolo. I remember him being difficult to dispossess and keeping things flowing smoothly.
Likewise, Barella had shown glimpses of class here and there. His eye for a pass, his ability to pick out a runner, or switch play effortlessly, his running in midfield etc. these were always on display at Cagliari. But it just wasn't enough tbh.
Massive credit to him though, because like Sensi, he's taken it up a notch at Inter and risen to the challenge so far. Possessing nice skills and good footballing IQ is one thing, but being able to make your mark on a game is another thing all together and much more difficult. I didn't expect them to be able to be so influential, so quickly.
One game at a time, though. Many a player has failed to live up to expectations after a great start. In between his missed 1v1 chance and his 3 or 4 row-z shots against Prague, dude could work on his shooting though.