The striker hit a hat-trick against Crewe on Friday as the Scot's side continued their pre-season preparations and his manager is delighted he is still at the club
The Belgium international found the target three times within 24 minutes, with Andreas Weimann and Leandro Bacuna also getting their names on the scoresheet at Gresty Road on Friday.
Benteke recently signed a new four-year contract at Villa after originally handing in a transfer request and, after a debut season that brought 19 Premier League goals, Lambert is confident the striker will continue to improve.
"I keep repeating myself, he's 22 he's not the finished article by a long shot," he told The Birmingham Mail.
"But he's been brilliant since I've been here at the football club. It's a big bonus that we've got him again and he can do very, very well."
The victory was Villa's first of pre-season, with four draws and a defeat in their previous fixtures and Lambert believes his players are improving ahead of the new campaign.
"Some of the football was excellent - that was more like it," he continued.
"I thought the performance was very good. I'm disappointed to concede a goal, but the way we played and our application was very good.
"There were a lot of pluses there, more than there has been. There's still a long way to go and a lot of work to do, but we're certainly getting there."