I am not surprised that Baca is one goal down in the first half because it is possible that Bacra will equalize the goal in this first half and take Thebes lead maybe in the second half. One thing I know is that Rayo will not win Barca because they are not as strong as Barca.
In Barca first match this season against Valencia, this was how Valencia scored first before Barca but it turned out that Barca equalized the goal and won the match with 2-1 victory against Villarreal. Betting on Barca does not mean that you have lost your bet yet until the game is over. If Barcelona did not score in this first half, the second half Willmar be in their favor.
Rayo Vallecano managed to score an early goal, and Barcelona had almost all of them to equalize, but they did not succeed, although there were good chances for this. Now if Rayo Vallecano concentrate on defense in the second half, it will be even more difficult for them, and the hosts may well choose such a strategy. For now, there is hope that Barcelona can turn the tide of this match, the half should be enough for this.