Freiburg became the fourth Bundesliga team to succumb to lower league opponents when they were beaten 3-2 at Unterhaching with Mijo Tunjic scoring two penalties including, an 87th minute winner for the third division side.
Hoffenheim had a narrow escape as they came from behind for a 3-1 extra-time win at sixth-tier Germania Windeck and Mainz 05 also needed extra-time for a 2-1 win at fifth tier Zweibruecken.
The German federation tries to maximise the chances of upsets by forcing Bundesliga teams to play away to lower league sides in one-leg first round ties.
Playing before the league season has started also increases the chances of shock results with VfL Wolfsburg, Werder Bremen and Bayer Leverkusen also losing to lower team opposition over the weekend.
Schalke had no such trouble as they raced to a 3-0 lead after only 13 minutes although Florian Kirstein headed one back for Teningen's amateurs, whose coach Claus Kraskovic warned he would substitute any starry-eyed player who tried to swap shirts with their illustrious opponents at half-time.
Dutch striker Klaas Jan Huntelaar led the way with four goals while Raul, Lewis Holtby and Mario Gavranovic scored twice each and Kyriakos Papadopoulos also got in on the act.
Hanover 96, who suffered first round defeats in the previous two seasons, made no mistake this time as they routed Wismar 6-0 while Hertha Berlin won 4-0 at Meuselwitz and Cologne 3-0 at Wiedenbrueck.
Second division Greuther Fuerth also hit double figures with a 10-0 win at Eimsbuetteler, Sercan Sararer scoring four.
