Bayern lead the way in the top flight with 20 points from eight league games and beat VfL Bochum 5-0 on October 27, while the visitors are fourth with 15 points after eight matchweeks and drew 1-1 with Eintracht Frankfurt last Sunday.
Match preview
The Bavarians were utterly dominant against Bochum, creating six big chances, registering 11 shots inside the penalty area and accumulating 72% possession.
The win was a welcome boost to Kompany, who presided over a humiliating 4-1 defeat against Barcelona on October 23, a defeat that left them in 23rd place out of 36 teams in the Champions League table.
In their last outing on Wednesday, the hosts beat Mainz 05 4-0 in the second round of the DFB-Pokal, with Jamal Musiala scoring a first-half hat-trick.
Bayern have now scored 20 goals in their five most recent games, as well as 24 times in their last six league matches.
Kompany's side are one of two unbeaten teams in the top flight and have won six of their last eight Bundesliga fixtures, winning their most recent two by a cumulative score of 9-0.
The Bavarians have also won five of their last six league games at home, as well as winning 15, drawing one and losing just one of their last 18 matches at the Allianz Arena.
As for the visitors, they come into Saturday's clash having lost 2-0 against Arminia Bielefeld on Wednesday in the second round of the DFB-Pokal, a match in which the Iron Ones created just one big chance.
Union Berlin drew 1-1 with Eintracht Frankfurt in their most recent league game and while many teams would ordinarily be pleased with a point against Dino Toppmoller's side, boss Bo Svensson may feel that his team should have mustered more than one shot after their opponents had been reduced to 10 men in the 77th minute.
Svensson's side currently occupy a Champions League qualification spot despite having scored just nine goals in eight games, making them the league's third worst offensive club.
To their credit, Union Berlin have conceded just five times, and this record is only bettered by Marco Rose's RB Leipzig.
The Iron Ones have lost three, drawn one and won one of their last four matches, though they have won two and drawn one of their last three Bundesliga games.
However, the away side have been poor away from home for some time, losing 12, drawing six and winning just two times in their 20 most recent fixtures on the road.
Bayern Munich Bundesliga form:
W
W
D
D
W
W
Bayern Munich form (all competitions):
L
D
W
L
W
W
Union Berlin Bundesliga form:
D
W
L
W
W
D
Union Berlin form (all competitions):
W
L
W
W
D
L
Team News
The hosts will be unable to call upon midfielder Aleksandar Pavlovic until the middle of December, while defenders Hiroki Ito and Josip Stanisic will likely be unavailable until late November.
Right-back Sacha Boey will also miss out until the middle of November, so expect Raphael Guerreiro, Dayot Upamecano, Kim Min-jae and Alphonso Davies to start in defence.
Joshua Kimmich may be partnered in a double pivot by Joao Palhinha, while Serge Gnabry and Michael Olise could flank striker Harry Kane.
As for Union Berlin, they will be without forward Ivan Prtajin and goalkeeper Yannic Stein until the middle of November, so perhaps Frederik Ronnow will start between the posts, while Benedict Hollerbach could feature up front.
Right-back Josip Juranovic is also expected to miss out due to injury, with Danilho Doekhi, Kevin Vogt and Diogo Leite candidates to start in a back three.
Midfielder Lucas Tousart will not make an appearance, and Aljoscha Kemlein and Rani Khedira may play in a double pivot considering Tousart's absence.
Bayern Munich possible starting lineup:
Neuer; Guerreiro, Upamecano, Kim, Davies; Kimmich, Palhinha; Olise, Musiala, Gnabry; Kane
Union Berlin possible starting lineup:
Ronnow; Doekhi, Vogt, Leite; Trimmel, Kemlein, Khedira, Rothe; Jeong, Hollerbach, Vertessen
We say: Bayern Munich 2-0 Union Berlin
Despite their impressive defensive record, is difficult to see how Union Berlin can keep Bayern Munich from scoring on Saturday given the hosts' rampant offensive displays this season.