Real Madrid president Florentino Perez was present to see the Castilla beat Cadiz 3-0 in their promotion playoff clash.
Esteban Granero was also in attendance.
Castilla coach Alberto Toril said: "Cadiz are a great side, so we're not done yet. We will try to play a good game for our supporters. We have to be calm this week and have respect for Cadiz, who were also group leaders.
"Knowing the President and the first team players support us makes us soar. We will try to seal promotion in the next 90 minutes."