The winners of the tie will advance to a second-stage encounter with FC Zurich later this month; with the losers being consigned to the Europa Conference League.
Match preview
Perhaps ruing their inability to capitalise on a positive first-half display in Poland, Qarabag's latest attempt to reach the Champions League group stage for the second time ended in a 1-0 loss last Tuesday.
The Azerbaijani champions suffered their first defeat against Polish opposition in Europe, as Lech Poznan captain Mikael Ishak found the decisive goal at Stadion Miejski Poznan, following a pass from Portuguese full-back Joel Pereira.
Having previously participated in 18 editions of UEFA competitions - including seven times in the Champions League, 13 in the UEFA Cup or Europa League, and two in the Cup Winners' Cup - Qarabag were the first Azeri club to advance to the group stage of Europe's top tournament, back in 2017.
If they are to continue their quest to replicate that achievement, long-serving coach Gurban Gurbanov - who led his side to the knockout stage of last season's Europa Conference League - must now engineer a victory on home soil.
Qarabag returned to first place in the Azerbaijan Premier League last term, having previously failed to claim the title for the first time in eight years - and will play host to Poznan as national champions.
Also completing a double by winning the cup in May, the Horsemen are undoubtedly top dogs in domestic competition, but now seek success amid Europe's elite.
If two losses from three warm-up games had caused concern in the Lech Poznan camp, last Tuesday's victory over Qarabag puts the Polish champions in a strong position to progress to the Champions League's second qualifying round.
The tenure of new coach John van den Brom began with a win from his first competitive match in charge, but it took just a few days for the gloss to wear off the ex-Anderlecht manager's start.
On Saturday, Lech lost to 2-0 to Rakow in the Polish Super Cup, with the Dutch coach making many changes to his starting XI due to the unfortunate timing of the fixture.
Though Lech had wanted to postpone the match - suggesting an alternative date in the middle of November, just before the World Cup - it went ahead, and they were beaten by goals scored shortly before and after the half-time break.
Nevertheless, after celebrating the club's 100th anniversary by lifting the Ekstraklasa trophy for the eighth time, under former boss Maciej Skorza, Lech are now aiming to make an impact on Europe.
Since the turn of the century, the Railwaymen have only four Europa League or UEFA Cup group appearances to show for their efforts, with a solitary knockout phase qualification in 2011 being curtailed at the last-32 stage.
Holding a slim advantage from last week's first leg, though, they will surely fancy their chances of taking one step closer to the promised land on Tuesday.
Qarabag FK Champions League form:
Qarabag FK form (all competitions):
Lech Poznan Champions League form:
Lech Poznan form (all competitions):
Team News
Qarabag's challenge will once again be led by Brazilian forward Kady, who was the club's joint-top scorer last term, netting five goals in their Conference League campaign.
As midfield regular Patrick Andrade recently moved to Partizan Belgrade on a free transfer, Richard Almeida and Qara Qarayev will partner each other in the hosts' engine room.
Having appeared as a substitute last week, well-travelled winger Marko Jankovic could make his first competitive start, after the Montenegro international joined from Hapoel Tel Aviv earlier this summer.
Meanwhile, Lech Poznan made a number of changes to their team for the weekend's Super Cup defeat, but are set to be at full strength in Baku.
Antonio Milic, Jesper Karlstrom and Radoslaw Murawski are the players most likely to retain their places, as John van den Brom selects an XI similar to that which started the first leg.
Newly-acquired winger Heorhiy Tsitaishvili - on loan from Dynamo Kyiv - impressed on Saturday, so could force his way into the team, which should feature Milic and Lubomir Satka at the heart of its back four.
Qarabag FK possible starting lineup:
Magomedaliyev; Vesovic, Medina, Medvedev, Bayramov; Almeida, Qarayev; Kady, Andrade, Zoubir; Wadji
Lech Poznan possible starting lineup:
Rudko; Pereira, Satka, Milic, Rebocho; Murawski, Karlstrom; Skoras, Amaral, Tsitaishvili; Ishak
We say: Qarabag FK 1-1 Lech Poznan (Lech Poznan win 2-1 on aggregate)
As both sides carry a goal threat and are used to taking the initiative, there could be opportunities at either end, following a relatively cagey first leg.
The Polish champions should progress, but it may require a backs-to-the-wall effort to secure their passage to the second qualifying round.