Former Tottenham star Bale, who continues to be linked with a return to the Premier League, started on the bench as the two-time reigning Champions League winner advanced to the quarter-finals with a 2-1 (5-2 aggregate) victory over a 10-man Paris Saint-Germain.
The Wales international forward was introduced with 14 minutes remaining in Paris.
"The team is the important thing," Zidane said. "Bale didn't play in the first leg nor today, but that doesn't have anything to do with it.
"He's very important and will be right to the end."
Bale was named among the substitutes as Zidane turned to Lucas Vazquez and Marco Asensio.
Vazquez was the provider for five-time Ballon d'Or winner Cristiano Ronaldo, who opened the scoring six minutes into the second half at the Parc des Princes.
Casemiro was also on target with 10 minutes remaining after Edinson Cavani pulled a goal back for the Ligue 1 leader.
"It was important to put them in to have two banks of four defending their wide players," Zidane said, referring to Vazquez and Asensio.
"We did that really well. Lucas is doing really well at the moment, and Marco too. We all are, but them in particular. I can't explain anything more to you.
"I have to choose every three days and today the plan was to go with those players. They did well."