You can never say Xavi's experience in the previous Champions League as a player could ever help this player to have a better performance as a coach while coaching Barcelona.
If I'm not wrong, he never coached any teams in the Champions Leagues before and Xavi is a completely inexperienced coach in this tournament. Since he had no experience as a coach but got good results in La Lga with Barcelona we can expect to see the same thing from him in the Champions League.
Of a truth Xavi is not really an experienced coach and had only had good experience in the Champions League as a player than coach, it was proven last season when they got demoted by Manchester united in the round of 16 to the Europa League but they still could perform well in the Europa League or even try to win it, atleast he managed to lead his team to winning the Laliga trophy and I think he should be given more time to build the Barcelona team, he's had an experience last season and could perform better in this seasons Champions tournament.
Though I can't vouch for them to win the Champions League under Barcelona but I expect them to perform better than last season and even go beyond the round of 16, my only fear is Lewandowski's form and if he continues miss chances it could affect their performance when the Champions League starts, however their rivals Realmadrid would have a better performance and probably reach the finals this season.