The score says how it ended. xG says how it should have ended: it is the sum of the chances each shot was worth, not an opinion about the game.
The score matched the game: Sassuolo was the better side by chances too.
Sassuolo: −0.6 for the season (10 in the table). Torino: −1.0 (14). The gap between points and xPTS is built from matches like this one.