Shakhtar Donetsk will recall tales of a famous victory away to Real Madrid forever and a day, yet for Los Blancos it will stand as a dark day in the club's history and one which has several key contributing factors behind it.
Zinedine Zidane is facing a difficult challenge to get things back on track in the Spanish capital, especially with their next challenge being the small matter of the first Clasico of the campaign.
With the French coach having admitted he has made mistakes with his team selections of late, the defeats to Cadiz and Shakhtar Donetsk could mark his second stint in charge at the Estadio Santiago Bernabeu.
Yet, is he completely to blame? A significant portion of the fanbase suggests no, however there are a significant number of problems at the club that were always going to lead to a night like Wednesday.
1. Zidane's experiments and the absence of a consistent XI
There was a time at Real Madrid when Zidane's backup team was made up of players of a certain stature: James Rodriguez, Isco, Marco Asensio, Mateo Kovacic and Alvaro Morata.
The present backup unit are not at that level and in a period of recession in Spanish football, decisions have been made which have left Zidane with an even weaker backup group than fans could have imagined.
In a season when matches will generally come every three days, Zidane has been forced to maintain his blind faith in rotations and selection experiments, but to this point that has only contributed to inconsistent performances and injuries.
Perhaps the most telling factor is that few supporters are capable of listing just what is the club's best XI that could start against Barcelona in an ideal world.
2. A failed attacking decision
Zidane surprised everyone by omitting Karim Benzema from his starting XI against the Ukrainian side, yet what was even more of a shock was the fact Luka Jovic was selected ahead of him.
Bear in mind that just a few short weeks ago, Zidane told the Serbian he could leave the club on loan, yet there he was starting an important Champions League match.
Zidane is desperate to find a way to get Jovic up to speed and rhythm in Madrid now he is staying, but his system struggles to accommodate a pure centre-forward which qualities to distant from those held by Benzema.
Asensio and Rodrygo on either side of Jovic simply didn't work, there was a lack of balance and attacking impetus.
The lack of service to Jovic was telling and he isn't the player who feed off scraps or make chances of his own, he needs crosses.
3. A defence that can't function without Ramos
Real Madrid will have to replace Sergio Ramos for good one day, and that day is closer than it is further away.
Yet, it is becoming increasingly clear that this Los Blancos defence can't even function in matches without the presence of the club captain.
It's been a theme in recent months that when Ramos isn't around, the defence collapses, especially in Europe. Los Merengues have lost six of their last seven Champions League matches where Ramos hasn't played.
Against Shakhtar Donetsk the central defenders looked all at sea with Raphael Varane unable to cope with the challenge of leadership.
Next to him, Eder Militao had the look of a lost child at a shopping centre, he was way out of his depth and played a significant part in two of the three goals the team conceded.
Any aerial pass from the visitors looked like it could force open a chasm within the Real Madrid defence, and this is something that just can't happen, especially with Ramos' career in its closing act.
4. Zidane made serious tactical mistakes
Few have ever claimed that Zidane is the tactical mastermind that Pep Guardiola is or that Jose Mourinho was in his younger days, with the Frenchman's main strength in his first period at Real Madrid being his ability to galvanise a squad that had achieved everything already.
However, on Wednesday evening the former Castilla coach made serious tactical errors which cost the team.
Zidane maintains he will die with his belief that his team should always look to put pressure on opposition players, but in order to do that his entire squad must be balanced and united.
It's a system that can't afford individual mistakes, but also struggles against teams that have pace in attack.
A high defensive line can be caught with aerial passes as happened with both Cadiz and Shakhtar, and both Marlos and Tete had a field-day all night long.
5. Vinicius Jr used as a last hope
With Los Blancos making no signings in the summer, Vinicius Jr has reappeared. With Santiago Solari he was used as the player to make things happen but it wasn't the best solution. Solari was too reliant on a player of such tender years.
Upon making his way onto the pitch on Wednesday, it took the Brazilian 15 seconds to score and give the hosts hope of a dramatic comeback.
The problem is that Zidane has never given the Brazilian confidence but with Eden Hazard out injured, the coach has no choice but to pile all the pressure on Vinicius Jr in the Clasico, just as Solari did.