The Magpies are currently fighting at the foot of the Premier League table, despite narrowly missing out on Champions League qualification last campaign.
Benitez, who takes his team to St James' Park today, remains wary of the talent within Alan Pardew's ranks.
"Last season they had a great campaign, and I was slightly surprised that they haven't been playing at the same level," Benitez told reporters.
"But you can see they still have good players, and I think they will do well, but hopefully after this game.
"They did well last Tuesday against Aston Villa, so they will be happy with the performance and the result. After this game, if they can win a few games in a row I'm sure they will be fine."
The Blues are six points off second-placed Manchester City.