Real won in the 86th minute with a Ferland Mendy curler using his weaker right foot from distance, so have the advantage going into the second leg.
“I did not expect it to be easy, as we know Atalanta are physically very strong and they proved it," Zidane told Sky Italia.
“We had a difficult game even against 10, but we scored a very important goal. That doesn't mean anything, though, as we still need to play the second leg and it remains 50-50.
“Atalanta are a side who can cause us problems on our own turf. Our performance was so-so, but the result was good. With what we'd seen of them, we knew Atalanta were a very good team and it would be tough."
Was Zidane surprised to see Mendy score with his weaker right foot?
“He has a right foot, I wasn't surprised by the goal, no."