The England international continued his great run in front of goal with another effort in the Blues' 4-1 win over Wigan at Stamford Bridge.
Benitez heaped praise midfielder, who is out of contract at the end of the season, but remained coy as to the Englishman's future beyond this season.
"In the last two months he has scored eight or nine goals, that's really pleasing for me. Lampard is fit, he understands the game, if he scores 20 goals and breaks the record I will be really pleased," he told reporters.
When asked how long the Blues' midfielder can continue playing for he joking replied: "If he is fit for Thursday, I'll be really pleased."
The Chelsea boss says that Chelsea held on to their lead well, during a nervy spell at 2-1 after Shaun Maloney had pulled one back for the visitors, because of the returning personnel which he has missed.
He continued: "The possibility to use different players was much better for us, David Luiz and Eden Hazard [returned] so we could move Ramires to the right side, which was crucial for us because they were playing three at the back.
"After you could change players, play [Juan] Mata, Yossi [Benayoun] and Marko Marin and they could make the difference, before we didn't have these options in some positions. Now we can manage the game in different ways."
The Spaniard also revealed that the Blues had been working on keeping leads in their training sessions, after dropping points from winning positions in recent weeks.
"We were working on the training session about that, the position, the shape of the team and what we have to do," he added.
"Oscar had cramp and Gary Cahill the same, the are playing too many games, but the good thing I'll say again, we can move David Luiz to center back, the last minute we can bring on Juan Mata from the bench, in the past we didn't have this kind of option."
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