The Gunners held off a late fightback from the home side at Villa Park to move back above Manchester City and Chelsea to the summit.
Lambert said: "That was more like it in the second half. I don't think if we'd got an equaliser anyone could have begrudged it."
Lambert was also pleased to see Benteke scoring again after a four-month drought. The Belgian had looked ineffective early on, but looked a different player when charged with confidence.
Lambert, who refused to comment on rumours linking him with a loan move for Wigan's Grant Holt, said: "About this time last year he started to hit the goals. It is quite uncanny. It will certainly give him a big lift."
Villa lost defender Nathan Baker early on to a sickening-looking injury after being hit in the face by a Serge Gnabry shot.
He was carried off on a stretcher wearing an oxygen mask after suffering mild concussion, but his condition was later reported as not serious.
Lambert added: "He is a little bit groggy but he is ok. He can't remember a thing about what happened."
- Christian Benteke
- Jack Wilshere
- Olivier Giroud