Barca have managed to secure the registrations of Olmo and Pau Victor for the short-term, meaning both can play against Real Madrid.
Flick says Olmo is being considered for selection for Sunday.
The match:
"They are one of the best teams in the world, but we are prepared to do it . We have to correct mistakes because they can take advantage of any opportunity."
On Dani Olmo and Pau Victor:
"Olmo can play, he has no problems. He will be back with the team. There is only noise from outside, we have to be together and strong."
On Inaki Pena and Wojciech Szczesny:
"We have a good match and Iñaki has played a fantastic first half. In Spain there is a different mentality. Abroad everyone talks. Everyone is professional. These are special matches and you have to be prepared. It is the third time that they (Jules Koundé and Iñaki) have arrived late."
On Vinicius Jr being able to play for Real Madrid despite his LaLiga ban:
"It's not my decision. It's good to have him in the Supercopa. Everyone wants to see the best players.
"This is a Clasico and a Supercopa final. If we win this we will have more confidence for the rest of the season."