Holding a 2-0 away lead from the first leg, Madrid repeated the performance at home, with goals from Cristiano Ronaldo – his 13th of the campaign - and James Rodriguez securing their progression in the tournament.
“It was a difficult game but in the end we achieved our objective, which was to go through,” Zidane told Uefa.com after the game. “And we didn't concede a goal. Over the 90 minutes a lot of things could have happened because we were up against a team with good, fast footballers. But we got the job done.”
Zidane then lauded his two goal-scorers, before revealing his pleasure at being able to rest a little before their next La Liga fixture on Sunday.
“I'm happy with James's goal,” he said. “He is training well and it's always important for a player like him to score. Every time Cristiano Ronaldo is on the pitch he wants to score and he keeps doing it.
“We can now look forward to the draw and relax. We need to rest.”
Los Blancos take on Las Palmas in their next League encounter at 21:30 on Sunday night.