
Marlon Ritter put the visitors in front in the 53rd minute when his header slipped through the hands and legs of Saarbruecken keeper Tim Schreiber.
Almamy Toure’s header in the 75th minute made sure of a place in the final for second division Kaiserslautern for the first time since 2003.
It also snapped a scintillating run for Saarbruecken, who had eliminated three Bundesliga clubs in the previous three rounds, including Bayern Munich.
Kaiserslautern will play the winners of Wednesday’s semifinal between Bundesliga leaders Bayer Leverkusen and second division club Fortuna Dusseldorf in the final in Berlin on May 25.