Xavi has learned from the defeat of Manchester United and Almeria, defense has been the priority of Xavi due to conceding three goals in his last two matches. In this prestigious match the Barcelona defender played with brilliant, Kounde, Alonso, Araujo and Balde played so spectacularly, they survived very well which made Real Madrid players unable to score a single goal in this match despite controlling the game.
As a result of the clever tactics used by Xavi, Madrid failed to make shots on target at home for the first time in the last 13 years. The second leg will be very beneficial for Barcelona, besides playing in front of his supporters, Barcelona has a capital of one goal at the Santiago Bernabeu.
Xavi's strategy in the El Clasico match was correct, but of course it's not Barcelona's style.
I think Xavi was really forced to play defensively because they don't have good squad to play in attack. This proved to be effective even though I found it very tiring. Losing Dembele, Pedri and Lewandowski was why Xavi did it, but it worked.
I've said that Barcelona wouldn't be so bad without those 3 players, but of course that only has to make Barcelona play strong in defense and take the few chances to win. In fact I almost thought Barcelona would have scored 2 goals if Kessie's shot had not hit Ansu Fati before the end, but winning an El Clasico match like this is very unusual for Barcelona. Due to Barcelona's excellent defence, Real Madrid were unable to have a single shot on target in their 13 attempts.