You are not supposed to do that. Alonso knows it and we do as well. But to punish the player for having that reaction when your team has just saved the game on the last minute of stoppage time seems quite ridiculous. Xabi Alonso will miss the UEFA Supercup against Sevilla because Michel Platini's Association decided to ban him for one European game because of that celebration you're watching above. Simeone will also have to sit one game out.
That means that Carlo Ancelotti will have to find a replacement for the Spanish midfielder once again after having to start that Champions League Final with Khedira playing in what's not his natural position. Asier Illarramendi will likely get the chance to be Alonso's backup considering that he's going through the whole preseason with the team, something that Modric, Kroos and Khedira are not doing because of their activity during the 2014 FIFA World Cup.