I thought he played well. Yea, he got dribbled once, but Douglas Costa was kept pretty quiet most of the game. Played some good passes when he had the chance to do so. I trust him on the ball and for a newcomer, that's a lot. I don't have as much trust on Roberto at RB, and think he is more error prone and not as good at physical duels. Semedo is pretty physical as well, hard to get past. Even wins headers on a regular basis. Plus, he is one of the fastest fullbacks out there.
As a minus, he has a bad habit of going into dead ends when he goes up.