Arminia Bielefeld captain Mael Corboz said his team's recent struggles have hardened their self-belief after the third-tier side beat holders Bayer Leverkusen 2-1 on Tuesday to reach their first German Cup final following a relegation battle last season.
Bielefeld have sent four Bundesliga teams spinning out of the competition in consecutive rounds to become the fourth third-tier side to reach the final.
Visitors Leverkusen led in the 17th minute through Jonathan Tah but Marius Woerl equalised three minutes later and Maximilian Grosser scored the winner on the stroke of halftime.
"Every round was surreal. I could not really believe it," American midfielder Corboz told reporters after his side had earlier eliminated Union Berlin, Freiburg and Werder Bremen.
Arminia flirted with relegation from 3.Liga last season, finishing six points above the drop zone.
They are fourth in the current campaign, six points behind leaders Dynamo Dresden.
"It was the worst case scenario to concede under the first 20 minutes but we have been through so much this year and last year. In a relegation battle in the third division and one year later we are in the DFB Pokal final," said Corboz.
Bielefeld will face the winner of Wednesday's semifinal between VfB Stuttgart and RB Leipzig in the final at Berlin's Olympiastadion on May 24.
"The fans had been saying we are going to Berlin since January," added Corboz.