Xabi will succeed but he is facing selection challenges. You cannot keep a player like Vinicius Junior on the bench when he is fit. I am glad the new coach is featuring young players like Rodrygo and Arda Güler but introducing Vinicius in the second half is wrong. We saw his impact immediately when he came in, giving an assist and scoring a goal. The best solution might be letting Rodrygo leave for another club because both players (Vinicius) are too good to be on the bench.
It is better to start a game with players who can propel and project your tactics. Vinicius Jr is not that guy that presses enough. Good thing I saw with my own eyes when they played against PSG during the Cwc. I'm cool with him coming from the bench until he learns to press and also add to his defending skills rather than stroll around. I don't watch this football with sentiment, Vinicius Jr need to convince Xabi Alonso into doing that.
Xabi Alanso knows what needs to be done to ensure the team continues to improve, as evidenced by his player rotations. He also had the courage to bench Vini and give Rodrygo the opportunity to play in his natural position, which was evident. Rodrygo performance in that match was impressive, even though he couldn't score, but he continued to pressure the opposition throughout. When Vini came on, it was natural for him to provide assists and goals because the opposing defense was already tired.
However, I believe rotations like this should be implemented frequently. This kind of variation allows players to develop equally, so there's no such thing as a star or special player everyone should play as a team. Xabi decision to come off the bench is sometimes beneficial, allowing him to observe the game and listen more closely to Xabi's instructions. However, there's one downside to Vini he can't control his mouth. In that match he knew he'd received a yellow card, but he still spoke loudly to the referee. Luckily Mbappe came to cover his mouth.