The big striker converted Roberto Firmino’s low cross just past the hour mark and despite some anxious moments late on, Liverpool held on for a first win in four, condemning Leicester to just a second league defeat of the season.
Having opted for Divock Origi over Benteke in attack, Jurgen Klopp will have been pleased by the way his side started the game, Philippe Coutinho curling a shot just wide of the far post in the third minute.
Liverpool appeared to be trying to match up with Firmino often playing right up alongside Origi in a 4-4-2.
Leicester soon showed their teeth though as Riyad Mahrez skipped past Alberto Moreno and got to the byline, only to see his cross cut out by Mamadou Sakho at the near post.
The Reds gradually assumed control and Firmino threaded a pass through to Origi, whose shot was well blocked by Wes Morgan.
Klopp was forced into a change as the impressive Origi went down with what seemed to be a hamstring problem and was replaced by Benteke.
That change – coincidentally, perhaps – was followed by Leicester’s best period of the first half and Mahrez went close to breaking the deadlock in the final minute of the half.
Leicester began the second half far brighter with Liverpool appearing to have lost the composure they showed before the break.
A scuffed pass from Sakho caused panic but with Dejan Lovren seeming to have resolved the situation, Mignolet played the ball back to Sakho, who have two men within two yards of him and he was forced to make another hurried clearance.
Liverpool eventually settled down again and Benteke headed just over from Henderson’s right-wing cross.
Five minutes later and he was celebrating, Firmino cutting the ball back for the Belgian to score his first goal since the end of October.
Liverpool should twice have sealed the win in the closing stages, first as Henderson ran through with two men for support before playing the ball to no one having reached the penalty area.
That was nothing compared to Benteke’s miss in the final minute, though, as Firmino played him in for an open goal with Schmeichel stranded up field having gone up for a long throw.
The Belgian contrived to shoot straight at the only defender back – Morgan – with the goal gaping before Lucas headed the rebound wide.
But it mattered not in the end as Liverpool held on for the three points.