Zidane's 81.8 winning percentage is now the best of any Real coach.

"When you go two goals up you have the game in your hands, but one goal for the opposition changes everything," said the manager.

"They go in at halftime more confident. It was our third game in a week, a lot of rain, less concentration ... all of which made everything more difficult.

"Having said all of that, we are happy because we are still the leaders and on a great run."

Madrid's fine form will be fully tested when it travels to face Barcelona next Saturday in the first Clasico of the season.

However, Zidane insisted there is no need for concern ahead of a meeting with Barca's fearsome frontline of Lionel Messi, Luis Suarez and Neymar.

"There is no concern," he said.

"We have a week ahead of us to work, work and work some more."