England forward Raheem Sterling had been lacking the sharpness of his early-season form in recent weeks, but looked back to his best as he orchestrated Liverpool’s brightest attacking play and set up Henderson’s goal with an incisive cross.
However, the youngster also missed a golden chance to put the game beyond the home side with 10 minutes left, steering straight at Ludogorets keeper Vladislav Stoyanov when clean through.
Liverpool’s current lack of self-belief was clear to see in the closing stages, the visitors retreating nervously as the home side pressed.
But although Terziev’s far-post header earned Ludogorets a deserved point, it does not alter Liverpool’s task against Basel on 9 December.
Rickie Lambert is the first English forward to score for Liverpool in the tournament since Peter Crouch on 28 November 2007.
Liverpool have now kept only one clean sheet in their last 10 Champions League matches