The result sees Real now facing a playoff to reach the round of 16.
Ancelotti said: "It was a good game. We played well today, we looked solid and well disciplined. We're very happy. It's a shame we couldn't wake up that little bit earlier in the competition but we're pleased to be in this kind of form at this stage.
“We were strong defensively and going forward as well. We're in good shape and there's a positive vibe around the place. We want to keep it up. It was a good performance today, no doubt about that.
“We have to wait for the draw. If we get City, it will be difficult for both sides but we have to wait for the draw. City have more chance of winning the Champions League than Celtic, given their structure and the quality they possess. We don't like playing them, but if that's who we get, then we'll play them just as we have in previous years.
“It won't really hurt us to play an extra couple of games because the team is in good shape both physically and mentally. We look more solid and I have full confidence in this team because I like what I'm seeing out on the pitch."
He added, “We have to respect the table. I don't like this format because there are too many games and my idea for football comes with getting rid of games for the players, not adding them."