The day after the Brazilian made an official statement pledging his future to Milan, Ancelotti said Friday that there is no hope of persuading Pato to change his mind.
''It was Pato's decision to stay there, we have to respect that decision,'' Ancelotti said. ''We have to look forward now. I don't think it can be reopened. It's finished.''
Despite missing out on Pato and on signing former England captain David Beckham, PSG has already spent close to ?90 million ($116 million) on players this season.
Ancelotti expects more signings before the end of the month as PSG bids to win the league title for the first time since 1994, and to qualify for the Champions League for the first time in eight years.
''We want to bring great players to PSG, and the transfer window is still open for a long time,'' Ancelotti said.
Ancelotti takes charge of his first league game at home to Toulouse on Saturday when the French league resumes after its winter break.
Ancelotti's first game as PSG coach was a scrappy 2-1 win against amateur side Locmine in the French Cup last weekend.