With Alonso as Real Madrid's headcoach, and a former player of Madrid, and a club which he played for many years, he's going to have a great achievement and success with Madrid, considering his successful managerial record with Leverkusen.
I believe they have higher opportunity in this competition to lift this very trophy aside, PSG and Chelsea two current champions.
Real Madrid is very lucky to have a coach like Xavi Alonso come into their rescue, because they had a poor last season under Carlo Ancelotti, and I do believe Alonso will get Madrid right back on track with his tactical system of play.
First off being a club legend and a good contributor in his time at Real Madrid doesn’t guarantee he will achieve great things or be successful as a manager with the same club it just has to be based on his managerial performance and capabilities. For the sake of his success with Leverkusen which raises the bar for him, then I can say their is a huge possibility that he will be successful but not because he is a legend with Madrid.
Yes, moreover, it is still too early to judge now because we do not know what will happen next season. Xabi Alonso comes as a coach, which certainly carries more pressure than just being a player. What is clear is that Xabi Alonso must show his ability to bring his former club to success because the club and fans have high hopes for Xabi Alonso, although I myself cannot say that Xabi will be successful at Real Madrid, but whatever Xabi's decision in managing the team must be supported by the management so that Xabi can be more flexible in setting the right strategy.