PSG have now drawn all of their three games in the French first division this season.
"We did not play good football," said Ancelotti. "We played without speed and away from opposition's goal.
"We must not lose confidence. We will improve. The team was more aggressive and well organised.
"New players have arrived or returned from injury. We must work more naturally like we did last year."
PSG are back in Ligue 1 action next Sunday when they travel to Lille.