The Blaugrana progressed into the quarter-finals of the Champions League by beating City 2-1 in Camp Nou, winning 4-1 on aggregate.
“Tata has managed the team very well from Saturday's loss to the game today,” he told AS.
“The team is fine physically. If not we wouldn’t have managed to play a good game against a team as powerful as City."
Zubizaretta went on to congratulate the team for their performance against the Premier League side and says he felt Manuel Pellegrini's side made it difficult for the Catalan giants.
“We played a very good game against a great opponent, who has a lot of talents, and wanted to have the ball but we have controlled the game.
“City came at us in the second half but that’s normal, they had to risk it, and we also created chances.
“The tie was decided over 180 minutes. We had a good lead from the first-leg but it could have become complicated."