A victory in Italy would have sealed Real's spot in the next phase but they had to content themselves with a point against Juve and know that a draw from one of their remaining two games will guarantee progress to the knock-out stages.
Juve bossed the first half and deservedly led at the break through Arturo Vidal's penalty.
However, Real turned the game on its head at the start of the second half as Cristiano Ronaldo and Gareth Bale scored in quick succession to make it 2-1 before Juve snatched a point when Spain international Fernando Llorente headed them level.
"In the second half, we played very well and were confident going forward and I'm happy with that," Ancelotti told a post-match press conference.
"In the first half, we played too deep and (Paul) Pogba and (Claudio) Marchisio caused problems for our defenders. Our midfielders were worried about their position and we didn't pressure them enough up front.
"We defended very deep in the first half, but in the second we pressured Juventus further up the field and had more possession and control of the match. We improved and the second half was very good."
Real goalkeeper Iker Casillas was in inspired form in the first half as he made his 133rd Champions League appearance, surpassing Raul's record for the club.
The 32-year-old has not been first choice for Real of late, with Diego Lopez often getting the nod between the sticks, but Ancelotti was quick to praise the veteran stopper.
"He has played fantastically, keeping his position very well and staying calm," he said.
"He had a very good game and was decisive in the first half because he made two great saves.
"We're lucky to have two great goalkeepers and I understand that for him it's not easy to not play so many games. He's very professional and is always ready to play."
Casillas' position as back-up at the Bernabeu has caused some consternation in Spain amongst media and fans alike but the Spain international insists he is content being in a rotation.
"I'm happy," he said. "I don't think that it is straightforward to get to be able to play now and whenever there's a chance I have to be at my best for the coach to be confident in me.
"It is hard to stay focused playing every two weeks but with help from the whole team it is easier to do well."