Benteke was forced off at Carrow Road just before the half-hour mark and his replacement Libor Kozak made an immediate impact by scoring the only goal.
Deadline day signing Kozak drew praise from Villa boss Lambert, who is also waiting for an assessment on the injury to key man Benteke.
"Christian slipped and the medical team are telling me it's his hip flexor," said Lambert. "Hopefully it's not too bad. I think he's not too bad.
"Libor came on and to be fair it was at a difficult time. He popped up with the goal that has won us the game.
"He's come here, with how fast it is, and he's endeared himself to the crowd which is great."
Lambert also praised his battered and bruised team for putting in a performance that was good enough to take all three points away from Carrow Road.
"The result was the most important thing rather than the performance," he said.
"What I am really pleased about is we had a few lads carrying knocks and we asked them to go out and perform. I thought they were brilliant.
"We were missing Jores (Okore) and Ashley (Westwood) who have been big players for us and we had to patch a few others up. In that opening 10 minutes I felt we could have been 2-0 up and then we conceded a soft penalty."
Brad Guzan saved Robert Snodgrass' fifth-minute penalty and kept the visitors ahead with a couple of fantastic second-half saves, with Lambert happy with his keeper.
"He made a brilliant save on the penalty," he added. "He played a major part in the result but that is what we pay him for. That is his job. His job is to make saves but he has been like that for me for the past year.
"This is a big season for him with the World Cup and for us but he is an absolute top pro and top man. I have seen him do it in training every day and his performances every day have been to that standard."