The 34-year-old reached the landmark in the Blues' 2-0 home win over West Ham on Saturday that moves them above Tottenham and into third place in the Premier League table
Lampard reached the landmark against his former with a first-half header and he is now just two goals behind Bobby Tambling's all-time club record.
"I'm happy because Frank has scored 200 goals, it's a fantastic achievement for anyone but particularly him," said Benitez. "I'm really pleased for him.
"Frank is a fantastic player and he works very hard in training. We have a lot of games to play this season, so hopefully he can score more goals.
"I don't take credit myself but I also give credit to the rest of the team because they give balance."
Eden Hazard scored Chelsea's second goal as they cruised to victory and moved up to third place in the Premier League table following Tottenham's defeat to Fulham.
Benitez believes the Blues are gathering momentum at the right time - they are also in the last eight of the FA Cup and Europa League - and has not ruled out challenging for second place after they moved to within four points of Manchester City.
"If we continue winning, you can be closer to second," Benitez added. "We have a busy schedule now and then we will see where we are in the table.
"Today we continued the momentum of playing attacking football and creating chances - we should have scored more goals.
"For me, if the team is playing well the fans will enjoy it. The main target for us is to stick together as a team and hopefully the fans will enjoy the results. I'm really pleased with the atmosphere and I'm really pleased with the team."