The hosts managed to hold perennial champions Bayern Munich to a 1-1 draw last time out, but Stuttgart were not so lucky against Borussia Dortmund, to whom they lost 3-2.
Union Berlin are not quite the force they once were in the early stages of the campaign, but Urs Fischer's side will fondly look back on their stalemate with Bayern Munich for a long time yet, as the two sides both chalked up a goal apiece at the Allianz Arena on April 10.
Bayern fielded a much-changed team due to their Champions League exploits, which ultimately ended in despair, but the highly-rated Jamal Musiala propelled them into the lead before Marcus Ingvartsen came off the bench to net just his third Bundesliga goal of the season for Union.
This week's hosts have struggled to get over the line more often than not since the turn of the year, but with only six games left to play, Union are very much in the European conversation as they sit seventh in the Bundesliga table - four points behind Bayer Leverkusen - although their recent form is sure to be a significant concern for the much-admired Fischer.
While Fischer's side have lost just one of their last eight in the premier division, they can only boast a mere two wins from their last 12, although their remarkable unbeaten home record is sure to serve them well against the newly-promoted side.
Indeed, Union Berlin have gone their last 13 league games undefeated at the fortress that is the Stadion An der Alten Forsterei, and Schalke 04 are the only team to prevent them from scoring on their own turf so far this season, but Stuttgart and their half-century of goals need no lessons in finding the back of the net themselves.
Out of the 50 league goals that Stuttgart have chalked up this term, 14 of them have come from Tottenham Hotspur-linked Sasa Kalajdzic, who is also being tipped to join Dortmund and become Erling Braut Haaland's heir apparent.
The 23-year-old showcased his qualities against the Black and Yellow last weekend as his 17th-minute header opened the scoring, and Stuttgart were 10 minutes away from claiming a point against the big boys, but the relatively unknown Ansgar Knauff netted in the 80th minute to steer Dortmund to a 3-2 success on the day.
Pellegrino Matarazzo's side ended the game with their heads held high, though, and a stellar spate of results since the start of February sees them sit just one point and two places below Union in the table, so the European dream is not dead and buried for the visitors just yet either.
While Stuttgart have claimed four victories from their last seven in the Bundesliga, three of those successes have come at home, as Matarazzo has witnessed his crop win just once on the road in their last six attempts - shipping 15 goals in that time - although the added incentive of being able to leapfrog their opponents with a win is more than enough motivation for Stuttgart to end their hoodoo away from home.
Union Berlin and Stuttgart played out a thrilling 2-2 stalemate earlier in the campaign - the fourth draw in five meetings between the two clubs - and the only other fixture saw Stuttgart win 3-1 in the 2016-17 2.Bundesliga campaign.
Union Berlin captain Christopher Trimmel suffered a broken nose in action against the champions last weekend, but the 34-year-old is expected to risk it this weekend and reprise his regular role on the right.
Taiwo Awoniyi, Sheraldo Becker and long-term absentee Anthony Ujah - yet to play this season - are not so fortunate with their injuries, but it would be a surprise to see Fischer make many alterations from the side that took a point off Bayern last time out.
Ingvartsen will certainly be eyeing a recall to the starting lineup, though, while Max Kruse will hope to avoid going three league games without a goal for the first time this season.
Stuttgart manager Matarazzo will be forced to cope without defender Marc Oliver Kempf after he was cautioned for the fifth time against Dortmund, so as long as soon-to-be free agent Gonzalo Castro makes a timely return from a thigh issue, Atakan Karazor should be free to move back into the defence.
On another negative note, Stuttgart confirmed a few weeks ago that Silas Wamangituka's season is over due to an ACL injury, while six-goal winger Nicolas Gonzalez is expected to miss out with a thigh issue.
Daniel Didavi once again came off the bench against Dortmund to score his side's second goal on the night, although it ultimately proved to be nothing more than a mere consolation, but he will hope to make a long-awaited start here.
Union Berlin possible starting lineup:
Luthe; Friedrich, Knoche, Schlotterbeck; Trimmel, Andrich, Promel, Lenz; Kruse, Ingvartsen; Musa
Stuttgart possible starting lineup:
Kobel; Mavropanos, Anton, Karazor; Coulibaly, Castro, Endo, Sosa; Didavi, Klimowicz; Kalajdzic
We say: Union Berlin 1-1 Stuttgart
An encounter between to evenly-matched teams with identical formations, lengthy injury lists and ambitions of Europe is the perfect recipe for another stalemate this weekend, and there has been little to separate them in meetings gone by. A moment of magic from Kalajdzic could determine the tie in Stuttgart's favour, but Union do not look like losing at home anytime soon, so we are expecting another share of the spoils this weekend.