Real Madrid will face Juventus in the round of 16, and it looks like Juventus will be a tough opponent compared to their previous opponents, so it will be interesting to see whether Xabi Alonso will continue to play with 3 defenders or perhaps he will experiment again using a different strategy.
The 0-3 victory over Leipzig is a good advantage. Xabi has made this change look apparent in their 3rd match, they played more organized. It seems Xabi wants to set a record and prove himself to win the first trophy. One of the proofs is Modric, who has agreed with Milan to still be brought to the Club World Cup. Xabi seems to be maximizing all the available players. Currently, in the knockout phase against Juventus, Madrid should win. I favor Madrid. Whether this is a one-off match or two, I do not know.