Real Madrid defeated Barcelona 4-0 at the Camp Nou, with Benzema claiming a second half hattrick.
The win helped Los Blancos overturn a 1-0 semi-final first leg deficit to reach the Copa del Rey final, where they will face Osasuna on May 6.
Benzema's hattrick was his second in successive games, having also scored three against Real Valladolid over the weekend.
The former France international has now scored 25 goals for Real Madrid in 31 games this season. Only Erling Haaland, Kylian Mbappe, Marcus Rashford and Robert Lewandowski have scored more among players from Europe's big five leagues.
Benzema won the Ballon D'or award in 2022 but missed the subsequent FIFA World Cup through injury.
Nonetheless, Ancelotti expects his talisman to challenge for the coveted individual award once more this year.
"Why not?" Ancelotti said following his side's 4-1 aggregate victory against Barcelona.
"He remains one of the best players in the world – and not just attacking players."
"The work he did during the international break helped him a lot," Ancelotti said of Benzema, who announced his latest retirement from France duty in December.
"He is in prime physical condition. With the qualities he has, he inevitably makes a difference for us."
