The club's £24million record signing, Bent, has been cast aside by Lambert for large parts of the season with the Scot preferring the Belgian international as the main target man.
And Benteke, 22, has repaid the boss by rattling in an impressive 23 goals in all competitions since his move from Genk last summer, while England international Bent is now considering his future at the club.
Lambert told The Sun: "I don't think about reputations. They don't win you games and, as an individual, you have to buy into the team. When I came in last year, it was a case of getting somebody to play alongside Darren.
"When the club lost Emile Heskey it needed a target man, a No.9.
"I wanted to replace someone of that ilk and Christian came in.
"Then I started looking at the squad, what system was going to suit, and ended up playing one guy up front - and the best one for that was Christian Benteke. And seeing his form, you can see why."
Lambert added: "There was nothing personal in it but we had to get a team that was going to win games.
"I stuck with it and I don't think anyone can argue with what's happened. Right from the off, Christian scored. He was an absolute cornerstone for us."