The 37-year-old midfielder was included for just his third start for PSG as the Ligue 1 leaders drew 2-2 with Barca in the first leg of their Champions League quarter-final at Parc des Princes.
Ancelotti felt the former England captain played well before coming off midway through the second half with a slight injury.
"Beckham played well," the Italian told Sky Sports News.
"He had a good pass at the beginning and for 30 minutes had good control of our play.
"After that he had a knock on his ankle and was not able to continue."
Blaise Matuidi scored PSG's second in the dying moments but will miss the return leg after picking up a yellow card, and Ancelotti admits he will be missed.
He said: "It is a bad blow because he is an important player. But we still have a lot of players in the midfield. I hope to get back Thiago Motta. We could also play with Clement Chantome, who has a good fighting spirit. I believe we will find a solution."
Ancelotti added: "We achieved a very good start to the match with a good attacking game. We defended well too.
"Unfortunately we conceded two goals: the first one is a gift offered to Leo Messi and the second one is a gift offered by the referee.
"Anyway, I am very proud of the behaviour and courage shown by my players, but I am not happy with the result."