Villa were without a goal in over 10 hours of play heading into the match against the league leaders, so the decision to drop Benteke - who scored 29 goals in 60 outings during his first two seasons at Villa Park - was not warmly received by the club's fans.
But the Belgian has only netted three times in this campaign and Lambert felt his decision to leave him on the bench until the 68th minute was justified.
"Christian by his own admission he knows himself he hasn't been playing well - the big guy knows that, but you need to protect him as well," Lambert said in quotes reported by the Birmingham Mail.
"The decision to leave him out wasn't any harder than to leave anybody else out - that is football management.
"The best reaction even from my own playing career when you're left out is you make sure you get back in it and don't come out of it.
"He knows he hasn't been playing well - he has got to get that back which will happen, he will get it back."
Lambert, however, defended his target man, who has struggled with injury problems throughout his Villa career.
The Scot added: "He has only been in this country three years and the first year he was excellent, the second year he had a bad injury and he is just getting back to playing the game again."
Villa's tally of 12 league goals is by far the worst in the top flight and has contributed to leaving them 16th, two points above the relegation zone, with 14 games remaining.
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