Benitez was appointed the Newcastle manager earlier this month following the dismissal of Steve McClaren.
The Spaniard is used to managing clubs challenging for major trophies, but he is now in charge of a team who are in real danger of getting relegated to the Championship at the end of the season.
The former Liverpool and Chelsea boss has admitted that the Newcastle job is bigger than he had anticipated.
“Maybe - because you cannot control other things, it is more difficult,” Benitez told The Sunderland Echo when asked if the Newcastle job was a bigger challenge than he first thought.
“Everyone was expecting maybe Norwich not to get anything, but they won against West Brom so we have just have to keep doing well or better, because if not it will be very difficult.”
Newcastle are second from bottom in the Premier League table at the moment, and there is a very good chance that they will go down to the Championship.
Sunderland and Norwich City are the two sides in serious danger of getting relegated along with rock-bottom Aston Villa.
The Magpies need to improve their performances and start winning games in order to escape the drop.
Newcastle will return to action next weekend when they take on fellow relegation candidates Norwich away from home at Carrow Road in the Premier League.