German third-tier side Arminia Bielefeld's record against Bundesliga clubs in the German Cup makes them dangerous opponents, Bayer Leverkusen manager Xabi Alonso said ahead of Tuesday's semifinal between the sides.
Bielefeld knocked out Union Berlin, SC Freiburg and Werder Bremen on the way to the last four.
"We have to respect Arminia, they have beaten three Bundesliga teams already. We have to be ready for a tough game. We need to give everything, it's an all-or-nothing game," Alonso told reporters on Monday.
"The DFB-Pokal is special. It writes its own stories. Arminia has done very well and deserves to be in the semis."
Leverkusen, the German Cup holders, are on a two-match winning run after recovering from their Champions League exit and a loss to Werder Bremen in the Bundesliga.
They are second in the standings, trailing leaders Bayern Munich by six points with nine matches remaining.
"Arminia play with a lot of energy and are courageous with the ball. They are very dynamic going forward. It's semis, we're expecting a great atmosphere in Bielefeld and we'll have to give it our all," Alonso said.