Ancelotti admitted Beckham - who has made a single start since his deadline-day move - could have a significant role to play if PSG are to reach the last-eight for the first time in 18 years.
"Of course we need him (Beckham) as at the same time we need the quality and ability of the other players in this game," Ancelotti told a press conference.
"He has played two games (in the past week). The first game 85 minutes the other game 25. He played well with no problem.
"He has arrived at this team with his quality and his character - everything is Okay."