The Welsh ace continues to score vital goals for Spurs as they chase a Champions League spot and although Benitez is aware of his ability, he has implored Andre Villas-Boas to also be careful of the quality he will deploy at Stamford Bridge.
"I think he is a good manager, he is working hard for his new team," Benitez said. "They're in a good position and doing well.
"Bale is very good, having a great season and scoring a lot of crucial goals for them. He is playing in different positions and doing well in all of them.
"The way we play, we have a good team with good players. We have to keep an eye on him but they have to keep an eye on ours."