Fernando Wallace grabbed the only goal of the game against Levski Sofia to propel Gent into second place in Europa League Group C and set up a high-stakes final match.
Gent moved to seven points with the 1-0 win, two ahead of next opponents Lille, with runners-up spot now to be decided when they meet in a fortnight.
Things looked as if they would be even tighter going into that match with the scores locked at 0-0 until Wallace's 77th-minute intervention.
Zlatan Ljubijankic had the first chance of the match in the seventh minute but Dustley Mulder was on hand to clear the danger for Levski.
Yassine El Ghanassy also failed to breach the defence when he tried his luck from 20 yards in the ninth minute.
The Bulgarians began to assert themselves physically as the half progressed, incurring a series of fouls as they went in hard on the hosts.
Levski's first serious attempt went to Vladimir Gadzhev after 20 minutes' play, but his ambitious effort from 25 yards sailed wide.
Gadzhev went closer three minutes later, only for Stef Wils to close down his shot.
Both sides struggled for a final ball, Hristo Yovov's awkward cross which required Bojan Jorgacevic's attention aside, but Randall Azofeifa did force a smart save with a 36th-minute free-kick.
Jorgacevic had one more straightforward save to make before the half-time whistle, but Gent failed to hit the target through Bernd Thijs and El Ghanassy.
The second half began in familiar fashion, Levski conceding a handful of fouls and a couple of shots flying off target from outside the area.
Azofeifa and Shlomi Arbeitman combined 10 minutes after the restart only for the latter to see his right-footed shot saved by Bozhidar Mitrev.
The Belgians continued to move into a dominant position from that point, first Mario Baric and then El Ghanassy drawing good stops from Mitrev.
The Sofia stopper looked like the only obstacle in the way of a Gent win when he again parried an El Ghanassy effort 20 minutes from time and Arbeitman fluffed the loose ball.
But Wallace had other ideas, profiting from a swift counter- attack and sliding his shot over the line to end the stalemate.
There were to be no further goals though, ending Levski's interest in the competition and leaving Gent facing another tense outing against Lille.