A place in the playoffs - where Dinamo Zagreb will await - is the prize at stake for both teams, but Ludogorets lead by one goal after last week's first leg.
Match preview
It was a busy evening in Baku for Brazilian winger Caio Vidal, who not only headed home a late Ludogorets winner but then saw red for his second bookable offence just a few minutes later.
After Dinis Almeida had seen an opener cancelled out by Qarabag's own Brazil-born forward, Juninho, the Eagles struck again through Vidal, leaving them within touching distance of the Champions League playoffs.
Georgi Dermendzhiev's men were on a streak of six consecutive away defeats in qualifying for Europe's top club competition, but having now ended that run, they can take a precious lead into Tuesday's game at Huvepharma Arena.
Ludogorets have already come through two knockout contests just to reach this stage, seeing off Dinamo Batumi in their first qualifier, then edging past Dinamo Minsk 2-1 on aggregate in the next round.
Another Dinamo would provide their opponents in the playoff round - Croatian giants Dinamo Zagreb - but first they must get past an experienced Qarabag side.
Having already posted two wins from two in the First League so far this season - beating CSKA Sofia before putting five past Arda - the Bulgarian champions were treated to a rest at the weekend, so they should certainly be fresh for the fight.
While Ludogorets won their 13th consecutive title last term, Qarabag claimed top spot in the Azerbaijan Premier League for a 10th time in 11 years - only in the 2020-21 campaign did they come up just short.
As a result of their latest triumph, the Horsemen galloped into the Champions League qualifiers at the second round stage, where they crushed Gibraltar's Lincoln Red Imps 7-0 on aggregate; two league games have subsequently brought seven goals and six points.
Gurban Gurbanov's side have been regular fixtures in Europe since the long-serving head coach took charge back in 2008, and last term's Europa League run only ended at the hands of Bundesliga champions Bayer Leverkusen in the last 16.
After letting victory slip through their fingers on that occasion, Qarabag now have their sights set on reaching the new-look Champions League group phase, which would guarantee a minimum of eight high-profile matches between September and January.
Ludogorets Razgrad Champions League form:
W
L
W
L
W
Ludogorets Razgrad form (all competitions):
L
W
L
W
L
W
Qarabag FK Champions League form:
W
W
L
Qarabag FK form (all competitions):
D
L
W
W
W
L
Team News
After first-choice Sergio Padt was missing from Georgi Dermendzhiev's squad last week, it remains to be seen whether back-up goalkeeper Hendrik Bonnman will be called upon again, as Ludogorets seek to defend their first-leg lead.
Having previously scored twice in the league, Son replaced Aslak Fonn Witry at right-back last week, while Rick made way for Caio Vidal.
As the latter must now serve a suspension, Rwan Seco and Spas Delev will come into contention for a place in attack; Ghanaian winger Bernard Tekpetey was stretchered off in Baku and has since undergone surgery for a broken leg.
Swiss striker Kwadwo Duah - a scorer at Euro 2024 - should lead the hosts' front line, while Juninho provides Qarabag's main goal threat.
The former Chaves forward, who has found the net four times in his last two Champions League qualifying games, is set to start alongside Yassine Benzia and captain Abdellah Zoubir at Huvepharma Arena.
Montenegro internationals Marko Vesovic and Marko Jankovic are set to start in midfield and at right-back respectively.
Ludogorets Razgrad possible starting lineup:
Bonmann; Son, Verdon, Almeida, Nedyalkov; Naressi, Piotrowski, Nedelev; Rick, Duah, Delev
Qarabag FK possible starting lineup:
Buntic; Vesovic, Mustafazada, Medina, Bayramov; Jankovic, Romao; Andrade, Benzia, Zoubir; Juninho