Barcelona could not take advantage of playing at home. He should have scored the second goal and played the match more calmly. Since they could not achieve this, things started to turn around for them in the second half.
The course of the match in El Clasico can change at any time. If a team that is ahead acts as if they have won the match, the result may end in a way they never expected. Real Madrid increased its influence in the game with the changes it made and managed to gain the upper hand despite being away. Bellingham's contribution to the team is tremendous. Scoring 2 goals in El Clasico is a great achievement.
Barcelona will really have to pay for this loss in the nearest future as they will have other team who were somehow scared of them now rebuild their confidence and think they could challenge Barcelona to a win, because they will think if Barcelona could loose at home after leading earlier it could mean they are gradually becoming weak but I hope Barcelona gets over this loss quick enough to fave others in the laliga and UCL with a sound mind.
Real Madrid so far has had a beautiful week winning their UCL game and now ending the week with another victory against a big team in the El clasico is really a week worth celebrating. Interestingly they won all these games playing away, definitely they will have their morale high up and ready for a New week to take on their opponents fearless I'm the next fixtures.