The 34-year-old achieved the feat by opening the scoring against his former team West Ham United in an encounter that the Blues went on to win 2-0.
"He's a great player. 200 goals for any player is a fantastic achievement. For a midfielder it's even better," Benitez told Sky Sports News.
"He could have scored one or two more goals. I'm really pleased for the team, really pleased for him and for everyone here."
Lampard is now just two goals behind Bobby Tambling, who is Chelsea's leading goalscorer of all time.