The hosts will bring a slender lead into the second leg, with Samir Hadji's second-half penalty in Yerevan last week currently the difference between the two sides.
Match preview
Dudelange will not begin their domestic campaign until August 6, so they have been able to fully concentrate on the Champions League this season, running out 3-1 winners on aggregate against Tirana in the first qualifying round, which set up the contest with Pyunik.
There was not an awful lot between the two sides in the first leg last week, but a penalty from Hadji in the 72nd minute ensured that the Luxembourg outfit would take an advantage into this match.
Carlos Fangueiro's side advanced to the first qualifying round of this season's Champions League by finishing top of the Luxembourg National Division last season, picking up 67 points from 30 matches.
Dudelange competed in the group stage of the Europa League in both 2018-19 and 2019-20, but this is their first participation in the qualifying rounds of the Champions League since losing to Valletta in the first qualifying round during the 2019-20 campaign.
Pyunik, meanwhile, needed penalties to overcome CFR Cluj in the first qualifying round of this season's competition, with a 2-2 draw following a goalless draw, and the Armenian outfit ultimately won the shootout 4-3.
The Academy won the Armenian Premier League for the 15th time last season, finishing one point clear of Ararat-Armenia at the top of the division, which saw them secure a spot in the European Cup.
This is the first season that Pjunik are competing in the Champions League since 2015-16, when Molde beat them 5-1 on aggregate in the second qualifying round, while they suffered an 8-0 aggregate loss to Wolverhampton Wanderers in the third qualifying round for the 2019-20 Europa League.
Yegishe Melikyan's side are set to begin their league season against Ararat on July 30, so it is a balancing act for the manager when it comes to preparing for this contest.
F91 Dudelange Champions League form:
F91 Dudelange form (all competitions):
FC Pyunik Champions League form:
FC Pyunik form (all competitions):
Team News
Dudelange again lined up in a 3-4-1-2 formation against Pyunik in the first leg last week and that is also likely to be the case for the return fixture.
Hadji, who netted the winner last week, is set to be joined in the final third of the field by Mohcine Hassan, with Dejvid Sinani operating just behind the front two.
Mehdi Kirch will again captain the side from a wing-back position, meanwhile, with a back three including Manuel da Costa and Jules Diouf.
Pyunik have started with a 5-4-1 formation in all three of their Champions League matches this season, with Luka Juricic leading the line last time out.
Both sides will have had a full week to prepare for this contest, and neither has reported any fresh concerns, so there are not likely to be many alterations.
Uros Nenadovic and Renzo Zambrano are among those pushing for spots in the starting XI here, but head coach Melikyan is expected to resist the temptation to shuffle his pack for the second leg.
F91 Dudelange possible starting lineup:
Fox; Da Costa, Diouf, Skenderovic; Ouassiero, Bojic, Morren, Kirch; Sinani; Hadji, Hassan
FC Pyunik possible starting lineup:
Yurchenko; Gonzalez, Gajic, Kovalenko, Dashyan, Juninho; Davidyan, Cociuc, Harutyunyan, Otubanjo; Juricic
We say: F91 Dudelange 2-0 FC Pyunik
Pyunik have given themselves a mountain to climb in the second leg, and we are finding it very difficult to back them to turn the contest around. Dudelange have been impressive in the competition this season, and we are expecting them to win the second leg comfortably to progress to the third qualifying round.