This is definitely a concern, I watched the match between Real Madrid vs Osasuna live and I didn't like Real Madrid's performance either. Maybe they exchanged the ball a lot but what's the point of exchanging the ball if they can't attack well or they can't score goals. Real Madrid players got several chances especially at the beginning of the match Vinicius Junior passed a ball inside the opponent's D box to Mbappe with a great dribble but Mbappe couldn't finish the ball well. But Mbappe should have taken advantage of that chance.
Real Madrid got a penalty, it's their luck, if Real Madrid hadn't got a penalty then they would have finished the match with only one point. Barcelona secured a big win in their first match, on the contrary Real Madrid couldn't do that so if there is no big change in performance then Barcelona can go to the top of the points table like last season.