The England international netted a first-half penalty to help the Blues to a 2-0 win over the Welsh outfit at Stamford Bridge, which has left the 34-year-old just one goal short of Bobby Tambling's 202 haul for the club.
While he praised the performance of Lampard, Benitez joked that he would be far happier if the midfielder could add another handful of goals before the end of the season.
"Frank is a great player," Benitez told ESPN. "I'm really pleased he's scored another goal and hopefully he can score five between now and the end of the season and he'll be much happier and we will be the same.
"He's a good player with quality. When you're controlling and have more possession, he can have an influence, like today.
"He's a great professional. He's always really focused. He would like to play more games, but he understands that the main thing is the team and to qualify for the Champions League. He wants to play, but he understands the team is first."
Chelsea currently sit third in the Premier League table.