Bayern are unbeaten in 46 games against German opposition in all competitions, but Weinzierl is confident that they must be defeated at some point and that the cup gives them a good opportunity.
"We have strong faith that we can achieve the upset," Weinzierl told reporters. "We want to play with more guts than three weeks ago [in their Bundesliga defeat]. Even then they scored all the goals from set pieces. We need to change that.
"They will not keep on winning games forever. Every streak comes to an end some time. If they underestimate us just a little, we will be there. We have won seven of our 10 home matches, and drawn one. We take a lot of confidence from that."
Augsburg are currently 10th in the Bundesliga, while Bayern are top.