A strong Frontline has been a major problem of Madrid since the beginning of the season just that they managed to cover it in previous match and made it not too obvious until they met Atletico who exposed this weakness of theirs.
I wasn't expecting it to be an easy game with Madrid tho, because AthletiCo is not a week team at all to contend with in all sense.
Real Madrid did not have Vinicius in previous matches that is a big minus for their attacking power. They still created opportunities but Joselu simply could not convert too many of them to goals for Real Madrid. Joselu played only at acceptable level and at a big club like Real Madrid, it seems to be not enough.
Real Madrid won previous matches in La Liga with goals from an unexpected scorer, Jude Bellingham but before joining Real Madrid and suddenly had this excellent scoring streak, Jude has never made a similar streak in his career. He is not a goal productive midfielder like Frank Lampard in previous seasons. The transfer from Dortmund to Real Madrid and this season can be a big achievement and upgrade for Jude's career. However as a giant club, Real Madrid must wake up their attacking players to score goals for them and to reduce pressure as well as expectation on Jude Bellingham.
Even though they have always won previous matches, Real Madrid's performance seems to be starting to decline. This condition is of course very worrying for Ancelotti, he often manipulates formations in every match because the need for players, especially in the attacking sector, is very weak after Vinicius was injured. When conditions are lame like that, Ancelotti only relies on Bellingham as a shadow striker in his formation, it looks good, but if he continues to apply this, it will be very easy for opponents to read. And I'm sure Atletico Madrid will be able to read that gap and they will be able to win and not give their opponent a chance for a comeback.
Problems are always there but they only are shown more clearly with defeats and bad streak. This derby defeat is helpful for Real Madrid to wake up and realize their own weaknesses better. The season is long enough for them to improve and play better to win big titles. Weaknesses should be known in early phase of season as said, there will be enough given time for fixing. It's worse if dead weaknesses only shown in knock out phase and most decisive phase of season, then there will be no time to fix anything rather than losing titles and competitions.