Milan rescued a Champions League point thanks to a late header from Thiago Silva.
Ancelotti, watching the game for Sky Italia, remarked: "Milan took the field with the right attitude. (Alessandro) Nesta and Thiago Silva have been very good, they never let Barcelona's attackers get behind them.
"This did not allow Barcelona to create many chances. There was a hint of arrogance on the part of Barcelona. Sometimes they were a little too passive and defensive. It was a mark against them, but also AC Milan left them with few openings.
"Again, the attitude was right for the Rossoneri. And it's too dangerous to press the Barcelona midfield "