The first controversy emerged after just two minutes in El Clásico, as Javier Mascherano and Lucas Vázquez were involved in a clash inside Barcelona's box.
Los Blancos' wingman dribbled past Mascherano, and when the Spanish player seemed to be sliding down the left flank, Mascherano got in the way and apparently tackled him.
Real Madrid players demanded a spot kick, but referee Clos Gómez decided not to grant it.
Here's how fans felt about that controversial call.
"Lucas Vázquez was brought down by Mascherano and asked for a PK! Clos Gomez ignored him"
#BarçaRealMadrid 0-0 (3') ¡Ojo! ¡Lucas Vázquez cayó ante Mascherano y reclamó un penalti! Clos Gómez no señaló nada #ElClásico #LaLiga pic.twitter.com/rCUJCTzz7u
— Desmarque R. Madrid (@Desmarque_RMCF) December 3, 2016
How was that not a penalty on Vazquez? I guess 2mins in a #ElClasico is too early to send Mascherano off.
— M.A.J (@UItraSuristic) December 3, 2016
Mascherano could murder a Real Madrid player and bury him in the 18 yard box before getting called for a penalty
— Baha (@Baha) December 3, 2016
"Penalty by Mascherano not given, a wrong foul call on Modric, and that's the beginning. Let the party continue!"
Penalti de Mascherano no pitado, falta de Modric que no era...y lo que queda. Que siga la fiesta.
— Paula Pineda (@7Sempiterno7) December 3, 2016