The hosts saw off Eintracht Frankfurt in the knockout playoff to reach this stage, while the Turkish visitors earned automatic entry to the final 16 having topped their group earlier in the campaign.
Match preview
Union SG return to continental action on Thursday on the back of a successful Europa Conference League playoff in February, after falling just short of advancing in their Europa League group.
The Belgian outfit joined LASK Linz, Toulouse and English giants Liverpool in a tough group in Europe's secondary competition, and while they were unable to progress with a top-two finish, their eight points were enough to book a spot in the Europa Conference League playoff, with the campaign ending in a historic 2-1 home win over Liverpool.
A tough test against German outfit Eintracht Frankfurt then followed in the playoff, with a round-of-16 place on the line in the tertiary tournament, and Alexander Blessin's side booked their spot with an impressive aggregate win, drawing 2-2 at home thanks to goals from Mathias Rasmussen and Gustaf Nilsson before Cameron Puertas and Dennis Eckert fired them to a decisive 2-1 victory in the away leg.
Les Unionistes now return to action on Thursday in fine form, having recently beaten Club Brugge 3-2 on aggregate in the Belgian Cup semi-final, before most recently beating Leuven 2-0 away from home on Saturday to seal top spot in the Belgian Pro League regular season and guarantee a place in next season's Europa League thanks to goals from Ross Sykes and Casper Terho.
With spirits bound to be high in the camp, given their only defeat in the last 24 outings was in the first leg of their successful two-legged tie against Club Brugge, Union SG will now bid to make the most of home advantage and gain an edge in their round-of-16 tie with a sixth straight victory.
In their way stand a Fenerbahce side who will play their first continental football of the New Year, having missed the playoff round thanks to their impressive group campaign.
Following a second-placed finish in the Turkish Super Lig last time around and a successful qualifying run, Thursday's visitors entered the Europa Conference League group stage alongside Ludogorets Razgrad, Nordsjaelland and Spartak Trnava and set out to seal top spot and automatic passage to the final 16.
They would succeed in doing so, narrowly pipping Ludogorets to top spot on goal difference, having managed 12 points from their six matches including a decisive 4-0 beating of Spartak Trnava in the final round of games in December, with Edin Dzeko netting a brace alongside Ferdi Kadioglu's opener and a Dominik Takac own goal.
Ismail Kartal's side have been in fine fettle since that group success too, going 11 Turkish Super Lig games unbeaten in the new year and winning nine of those, including three straight triumphs heading into Thursday's game to remain within touching distance of leaders Galatasaray in the title race, beating Caykur Rizespor and Kasimpasa before most recently picking up a 2-0 win away at Hatayspor on Saturday thanks to goals from Bright Osayi-Samuel and Cengiz Under.
Now turning their focus back to their continental pursuits with the aim of going deep into the Conference League and challenging for the trophy this term, Fenerbahce will aim to build on their momentum and build a lead in the round-of-16 tie on Thursday before welcoming Union SG to Turkey for the second leg next week.
Union SG Europa Conference League form:
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Fenerbahce Europa Conference League form:
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Fenerbahce form (all competitions):
Team News
Alexander Blessin will field a similar Union SG starting XI to the ones which featured in their second-leg triumph away at Eintracht Frankfurt in the playoff round and their recent 2-0 win over Leuven in their preferred 3-5-2 shape, with defender Kevin Mac Allister and midfielder Kevin Rodriguez remaining sidelined by injuries.
Charles Vanhoutte missed the second leg through suspension after being sent off in the 2-2 home draw with Frankfurt, and while he is in contention, he may have to settle for a place on the bench, with Mathias Rasmussen, Noah Sadiki and Cameron Puertas having starred in the midfield in the away win and at the weekend.
In the absence of key defender Mac Allister, Ross Sykes will again join Christian Burgess and Koki Machida in a back three, while at the other end of the pitch, Mohamed Amoura will continue to lead the line having notched up 21 goals in 33 appearances across all competitions so far this season.
Similarly, Fenerbahce should avoid making many changes from their away victory over Hatayspor at the weekend, with defender Luan Peres and attackers Josh King and Irfan Can Kahveci continuing spells in the treatment room.
Defender Alexander Djiku will return to contention after being suspended for that win, though, and he will hope to join Caglar Soyuncu in the middle of the back four, with Italian veteran Leonardo Bonucci also hoping to start, while former Manchester United man Fred will compete to come into the midfield from the outset after Mert Hakan Yandas and Ismail Yuksek were preferred on Saturday.
In their 4-2-3-1 shape, Edin Dzeko will again get the nod over Michy Batshuayi to lead the line, having netted 22 goals so far this term, while Dusan Tadic, Sebastian Szymanski and Cengiz Under will line up in a dangerous supporting trio behind the Bosnian.
Union SG possible starting lineup:
Moris; Sykes, Burgess, Machida; Terho, Rasmussen, Sadiki, Puertas, Castro-Montes; Amoura, Nilsson
Fenerbahce possible starting lineup:
Livakovic; Osayi-Samuel, Bonucci, Soyuncu, Kadioglu; Fred, Yuksek; Under, Szymanski, Tadic; Dzeko
We say: Union SG 1-1 Fenerbahce
We anticipate a tight first leg on Thursday between two sides who have enjoyed pleasing European campaigns thus far and possess plenty of quality.