Ancelotti made the controversial decision to call Neymar, 34, up for the 2026 World Cup ahead of the likes of Chelsea striker Joao Pedro.
Neymar ended up playing just 37 minutes across his three games due to a knee injury and has since retired from international football.
In an interview with CNN Esportes, Ancelotti said: "He deserved to be there because of his quality.
"Neymar has already confirmed that he does not want to return to the national team.
"Neymar cannot be replaced because he was an extraordinary and unique talent. So, an irreplaceable player."
Brazil face Australia twice in the upcoming international break, while they will also go up against India for the first time in their history.
