The visitors are likely to head into the encounter at the bottom of the table, but they can move level on points with their opponents by claiming all three points in the capital.
Match preview
Few sides in European football endured as much contrast in 2023 as Union Berlin, who qualified for the Champions League for the first time in their history by finishing fourth last season, before occupying the relegation places at times during the winter months.
Their 2-0 against relegation rivals FC Koln five days before Christmas at least ensured that Die Eisernen did not spend the winter break within the bottom three positions, while they recorded a second successive clean sheet by drawing 0-0 away to Freiburg in their first competitive match back in January.
However, they were defeated 1-0 by Bayern Munich at the Allianz Arena on Wednesday, with Raphael Guerreiro's strike just after half-time proving to be the difference between the sides. The match had been rescheduled from being postponed due to bad weather earlier in the season, and head coach Nenad Bjelica will likely take plenty of confidence from his side's narrow defeat to the reigning champions.
The same will not be possible if they fall short of anything but a victory against Darmstadt on Sunday. Their opponents, who were promoted last season, have failed to win any of their last 11 league games, meaning Union Berlin will be heavy favourites to claim all three points at Stadion An der Alten Forsterei.
Indeed, since claiming seven points from their opening seven matches upon returning to the Bundesliga for the first time since being relegated in 2017, Darmstadt have collected just four points from their ensuing 11 games to fall to the bottom of the table.
However, Torsten Lieberknecht's side showed their fighting spirit by coming from two goals behind to claim a point against Eintracht Frankfurt last weekend, with goals from Julian Justvan and Christoph Klarer giving their side a precious point.
Die Lilien showed similar resolve to fight back on three separate occasions when drawing 3-3 against Hoffenheim last month, illustrating that they should not be written off from surviving at this stage of proceedings. While their defensive record is by far the worst in the division, they clearly have more firepower than some of the sides above them.
Despite Mainz having no fixture and Koln being thrashed by Borussia Dortmund, Darmstadt's 2-2 draw against Frankfurt was not enough to move them off the foot of the table. That will almost certainly not be the case if they can claim all three points against Union Berlin on Sunday, which will certainly be their target given that they face the league leaders Bayer Leverkusen in their next fixture.
Union Berlin Bundesliga form:
D
W
L
W
D
L
Union Berlin form (all competitions):
W
L
L
W
D
L
SV Darmstadt 98 Bundesliga form:
L
L
L
D
L
D
Team News
Union Berlin will remain without Croatia full-back Josip Juranovic due to a muscle injury, while Kevin Volland and Rani Khedira are both major doubts due to concussion and calf issues respectively. Should Volland be ruled out as expected after suffering a blow to his head against Bayern, Kevin Behrens would likely replace him in attack.
Given the short turnaround between fixtures, Bjelica may be tempted to further shuffle his pack. The likes of Andras Schafer, Jerome Roussillon and Brenden Aaronson were used as substitutes in Munich, and could be called upon from the start on Sunday.
Darmstadt, meanwhile, will travel without Aaron Seydel, Fraser Hornby, Braydon Manu and Marvin Mehlem due to injury. Matej Maglica and Mathias Honsak are also doubts to make the trip to Berlin due to a groin issue and illness respectively.
Former Norwich City defender Christoph Zimmermann will be on standby to replace Maglica should the 25-year-old fail to recover in time, but Lieberknecht is unlikely to make any other changes after earning a decent result against Frankfurt last time out.
Union Berlin possible starting lineup:
Ronnow; Knoche, Vogt, Leite; Trimmel, Haberer, Kral, Aaronson, Gosens; Behrens, Bedia
SV Darmstadt 98 possible starting lineup:
Schuhen; Riedel, Zimmermann, Klarer; Bader, Franjic, Holland, Nurnberger; Justvan, Skarke; Pfeiffer
We say: Union Berlin 2-1 SV Darmstadt 98
Union Berlin have brought in several new faces in the January transfer window, with Bjelica desperate to improve his side's form. However, it could take time for some of these players to bed in, even if they should have enough quality to survive in the end.
Darmstadt are a difficult team to read, but ultimately they are struggling to win games at this level for one reason in particular: their inability to keep clean sheets. We expect them to put up another fight on Sunday, but ultimately fall to a damaging defeat.