Barcelona is a big team based on their previous performance last season a lot of fans expected them to be very strong when they play against teams that are below their standard but the game against Rayo Vallecano Barcelona were not in their best performance you could see that in the ball possession and the attempts they made that day, the penalty that was awarded by Barcelona can't be ruled out because the referee awarded it if it wasn't a penalty the VAR would have signalled the referee for it to be reviewed once again before the final decision. Rayo Vallecano was strong in the game their performance was too powerful and they finally got back in the game to share points with Barcelona.
We need to let teams breath in fresh air sometimes and let them have space. It's not like Barcelona lost the game, they never expected the draw but it happened and they went home with 1 point. To me it's better than having a loss that will bring nothing to the team. People think that Real Madrid is now having the top spot on the league but it doesn't change anything in my opinion, if they lose one match and Barcelona refused to loss, they will climb and remain at the top.
That same match, Barcelona had many chances with clean shot on target, they also had good play but midfield of Vallecano were ready in that match, those guys were there reason why Barcelona couldn't do much as they intended. If they have done more like they did in the first half, the outcome would have been different. This is going to be a motivation to keep pushing until the next match but I still have faith in what they are going to bring the next coming matches.