#4 Quique Setien's questionable substitution
Barcelona controversially terminated the contract of Ernesto Valverde in January and replaced him with Quique Setien and more than a few questioned the wisdom in the decision.
For all of his self-proclaimed admiration of the 'Cruyff way of playing football', the hard truth is that the former Real Betis man does not have the coaching pedigree or CV to take on a job the size of Barcelona.
Results under him have been mixed so far and while there have been flashes of his aesthetic style, the Catalans were largely unimpressive in their midweek draw with Napoli in the Champions League.
With Junior Firpo having underwhelmed in recent weeks, Setien replaced his former protege in the starting lineup with Clasico veteran Jordi Alba, also playing with a compact system comprising of four midfielders.
This helped Barcelona exert a level of control in the game but with Real Madrid gaining the ascendancy, the Blaugrana gaffer elected to take off the ineffective Arturo Vidal but rather than replace him with another midfielder, he brought on Martin Braithwaite for his Clasico debut.
His bravery was almost rewarded instantly as the former Leganes man raced onto a pass and forced Courtois off his line but the folly of this decision was revealed in the passage of play immediately after.
The 28-year-old failed to track Toni Kroos effectively and it was the German's pass to Vinicius that paved the way for the Brazilian to open his scoring.
For all of his shortcomings going forward, Vidal is a fighter and with Lionel Messi not to be bothered with tracking back, the Chilean's combativeness proves invaluable when Barcelona are defending.
With his substitution, Real Madrid gained an instant foothold in midfield and before Setien could realise his error to bring on Ivan Rakitic, the damage had already been done.
The 61-year-old was in charge of his first Clasico and he admitted to wanting to enjoy the spectacle but after his side's performance and questionable tactics, he would undoubtedly feel the pressure in the coming weeks.