Ferland Mendy struck a late winner as Real took control of the round of 16 clash.
Zidane said, "They're physically strong, and they did a great defensive job. It's a good result for us and that's the most important thing. I don't think creativity is an issue as we scored, and didn't concede.
"We've got a lot of absentees but we're on the right track, we're strong defensively, didn't give up any chances and got our away goal.
"It was tough going, but it's a good result in the end. We weren't great with it being ten against 11, but the result is all that matters and so was the away goal. There's still the second leg to come and we need to win at home, too."