While the hosts have prevailed in their last three on the bounce in the German top flight, Frankfurt are winless since the third gameweek of the season.
A clash with an out-of-sorts Koln side represented the perfect opportunity for Union to extend their unbeaten run and cement their position in the top five, and Urs Fischer's men did just that in gameweek eight.
Liverpool loanee Taiwo Awoniyi got off the mark for the season with Union's first goal of the game before Ellyes Skhiri headed in the equaliser less than 10 minutes later, but Max Kruse popped up with the winner in the second half - his ninth goal contribution in eight Bundesliga matches.
Despite a relatively slow start to the campaign, the 32-year-old now boasts a remarkable record of four goals and five assists in the 2020-21 season and has been integral to Union's unbeaten run, with the in-form Kruse now looking to register a goal contribution for the fifth top-flight game in a row.
Fischer's men were the surprise package of last season but no-one is doubting their Bundesliga credentials now, and should RB Leipzig and Bayer Leverkusen both suffer unexpected home defeats to Arminia Bielefeld and Hertha Berlin respectively, Union - who have not lost since the opening day of the season - would move up to third with victory over Frankfurt this weekend.
Kruse and co will certainly be confident of recording a fourth-straight triumph against a Frankfurt side who, by contrast, simply cannot seem to get over the line in 90 minutes.
Adi Hutter witnessed his side take seven points from a possible nine in their first three games of the campaign, but Frankfurt have not tasted victory since the beginning of October and have shared the spoils in four of their last five matches in the Bundesliga.
However, it would be overly harsh to criticise Frankfurt's most recent performance as Die Adler managed to hold high-flying Leipzig to a 1-1 draw last Saturday, with Aymen Barkok breaking the deadlock on the stroke of half time before Yussuf Poulsen came off the bench to ensure that both sides walked away with a point apiece.
Despite languishing in 11th in the table, Frankfurt can take confidence from the fact that they have only suffered one defeat on the road so far this season, which was a 5-0 thrashing at the hands of Bayern Munich a month ago.
Union won 2-1 in the most recent meeting between the two sides - their first ever victory against Die Adler - but Frankfurt prevailed by the same scoreline at Stadion An der Alten Forsterei.
Union Berlin Bundesliga form: WDDWWW
Eintracht Frankfurt Bundesliga form: WDLDDD
Union Berlin's Sebastian Griesbeck lasted only half an hour before ankle problems forced him off in the win over Koln, and the 30-year-old is a major doubt for this one.
Grischa Promel is ready to deputise if required, while Marius Bulter and Keita Endo are in contention to make their return to the squad after recovering from coronavirus and a thigh injury respectively.
Meanwhile, Frankfurt are confirmed to be without last weekend's goalscorer Barkok, who has since returned a positive COVID-19 test, but Amin Younes could reportedly make his return from coronavirus here.
Union Berlin possible starting lineup:
Luthe; Trimmel, Knoche, Friedrich, Lenz; Promel, Andrich; Becker, Kruse, Ingvartsen; Awoniyi
Eintracht Frankfurt possible starting lineup:
Trapp; Abraham, Hinteregger, N'Dicka; Da Costa, Sow, Rode, Kostic; Kamada, Kohr; Silva
We say: Union Berlin 2-1 Eintracht Frankfurt
Union would be making a fatal mistake if they were to take Frankfurt lightly despite the visitors' underwhelming run of form, and Hutter's men should be able to welcome a couple more players back to the fold at this crucial time. However, Union are a side playing with unbridled confidence and a taste for goals, so we are backing Fischer's side to march to their fourth win on the trot this weekend.