The £85m summer signing played the full 90 minutes in Real's 2-0 Copa del Rey win over Osasuna at the Bernabeu.
"Bale played very well and was very dangerous," said Ancelotti.
"Everyone knows he had injury problems and he is a player that needs to be in optimal condition," added Ancelotti. "For that reason he played the whole game.
"In the second-half the game was more open and it suited him more, but we are all very happy with him."
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