Cosmin Moti took over in goal after the Bulgarians' first-choice keeper had been sent off, and his resulting heroics helped to see the club past Steaua Bucharest.
With the Bulgarians tied at 1-1 on aggregate in the playoff round against Steaua Bucharest, regular shot-stopper Vladislav Stoyanov brought down the visitors' Fernando Varela in the 119th minute, prompting a red card from Spanish referee Alberto Undiano.
With all three substitutions having been used up, the home side was unable to bring on reserve keeper Ivan Cvorovic.MORE: Alex Morgan upset at 159-degree temps | Transfer photos
But Moti, a Romania international, took over the goalkeeping duties for the dying seconds of extra time and the resulting penalty shootout and produced a remarkable match-winning display between the posts.
He went on to net the opening penalty before making two dramatic saves from Paul Parvulescu and Cornel Rapa to secure a 6-5 victory on spot kicks, sending the home crowd into raptures.
Ludogorets had earlier appeared to be heading out of the competiton as a result of a 1-0 first-leg defeat, only for substitute Wanderson to score a crucial 90th minute goal to send the match into extra-time.
Moti's heroics mean Ludogorets will line up in the Champions League group stage for the first time in the club's history, with six games against some of the biggest names in Europe a reward for the side's exploits so far.