There was a slight mistake that Xavi made, namely with a long passing strategy, it was seen when Gavi was playing with an automatic long ball that happened. If from the beginning Xavi used more of a tiki-taka press, the style of play and rhythm would be much different and the possibility of winning could happen. Here Xavi lost the game of tiki-taka because what he used was a long ball.
Great teams are always a struggle of tactics and a good execution of moments. It was with the implementation of chances that Barcelona had problems, because there were periods when Barca dominated and there was a feeling that a little more and there would be a goal, but Neuer worked perfectly in this match and saved Bayern several times from a goal. I don't know if there is Xavi's mistake here, Bayern are really stronger at the moment.