In the first of two semi-finals, the winners will be set up with a cup final against either Bayer Leverkusen or Fortuna Dusseldorf in Berlin in May.
Match preview
After becoming the first-ever fourth-tier side to make the semi-finals back in 2019-20 in their last DFB-Pokal appearance, Saarbrucken have incredibly reached the final four yet again.
They have done so this time as a third division club, and will become the first team since Union Berlin in 2001 to reach the Pokal final if they win here.
Reaching the final would be an unbelievable achievement for the club, who were the lowest-ranked qualifiers via the league route.
The top four from the 3. Liga gain access automatically into the Pokal, and even though Saarbrucken finished fifth last season, Freiburg's reserve team - who finished second - were not permitted entry, instead handing their slot down to Rudiger Ziehl's side.
Beating second-tier Karlsruhe was already a shock in itself, but that was nothing compared to what Saarbrucken have gone on to accomplish.
Taking down reigning German champions Bayern Munich, despite being odds of 45/1, was scarcely believable, and more giant killings were to come, as they defeated Eintracht Frankfurt and Borussia Monchengladbach to get this far.
The quarter-final win over Gladbach was only played shortly before the international break, as the initial game was postponed, the same fate which beset their weekend clash with Rot-Weiss Essen.
That means Saarbrucken have now not played since March 16, and with nothing left to play for in the league, having a fixture at the weekend would have provided good preparation for the third-tier outfit.
After not meeting competitively in almost 30 years, Kaiserslautern's relegation to the third tier in 2020 meant these two shared a division for two seasons.
It was Kaiserslautern who often got the better of Saarbrucken though, winning the previous three meetings, on their way to promotion back to the second tier.
In comparison to their opponent's incredible cup run, Friedhelm Funkel's men have beaten just one top-tier side - Koln in round two.
Mid-table 2. Bundesliga sides Nuremberg and Hertha Berlin were seen off comfortably in the round of 16 and quarter-finals, making Kaiserslautern second-favourites for the Pokal behind Leverkusen, given their kind semi-final draw.
The two-time winners enjoyed both of those successes in the 1990s, and were finalists as recently as 2003, but they would become the first second-tier finalists since Duisburg 13 years ago should they come out on top here.
There was no reprieve from recent poor form at the weekend though, as they remain deep in relegation trouble following a defeat to fellow semi-finalists Dusseldorf, meaning they have taken just eight points in their last eight games.
Reaching a major final would be a welcome distraction, given that Kaiserslautern currently occupy the relegation playoff spot, mainly due to seven straight losses between November and January.
Saarbrucken DFB-Pokal form:
W
W
W
W
Saarbrucken form (all competitions):
Kaiserslautern DFB-Pokal form:
W
W
W
W
Kaiserslautern form (all competitions):
D
L
W
W
D
L
Team News
Saarbrucken's match winner from the tie with Gladbach Kai Brunker went off injured just days after his heroics, in their league clash with Duisburg, making him a doubt for this one.
The hosts could also be without one of their goalscorers from the famous Bayern win, as Patrick Sontheimer missed that league encounter entirely.
There could be some personnel changes in defence for Saarbrucken, with Bjarne Thoelke likely to come in for Dominik Becker on the right-hand side of a back three.
Manager Ziehl may also choose to go with Calogero Rizzuto at right-wing back, with Robin Tim Becker possibly dropping out from the side that beat Gladbach.
Kaiserslautern are set to be without 15-goal man Ragnar Ache due to a hip injury here, removing a huge chunk of their threat in attack.
Philipp Klement, first-choice keeper Julian Krahl and Hendrick Zuck are also set to miss out due to lingering injury concerns.
Left-back Tymoteusz Puchacz will be looking for more knockout success after being part of the Poland squad which beat Wales to reach Euro 2024 last week.
Saarbrucken possible starting lineup:
Schreiber; Rizzuto, Thoelke, Zeitz, Boeder, Gaus; Naifi, Kerber, Civeja, Stehle; Rabihic
Kaiserslautern possible starting lineup:
Himmelmann; Elvedi, Tomiak, Toure; Ronstadt, Kaloc, Niehues, Puchacz; Ritter, Hanslik, Redondo
We say: Saarbrucken 1-2 Kaiserslautern
While the fairytale has been a magical one, Saarbrucken's lower stature makes them slight outsiders for this one, despite home advantage.