Bundesliga champions Bayer Leverkusen battled past second-division Kaiserslautern 1-0 on Saturday to win the DFB-Pokal (German Cup) and secure the club's first domestic double.

Leverkusen won the Bundesliga unbeaten, a historic feat. The only blip on the record of Xabi Alonso's team this season was losing the Europa League final to Atalanta 3-0 on Wednesday in Dublin. That ended Leverkusen's record 51-game unbeaten run across all competitions. It was their only loss in 53 games this season.

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This was Leverkusen's second German Cup win after their maiden victory back in 1993.

"In the end, to win like that meant we showed spirit, we fought for the fans for the club," Alonso said. "It is huge success to win the double. We will remember this in the future."

At Berlin's Olympiastadion, which will host the Euro 2024 final in July, Leverkusen took the lead with Granit Xhaka's 20-metre missile in the 16th minute.

They controlled the tempo even after they were reduced to 10 men following Odilon Kossounou's second booking a minute before half-time.

Kaiserslautern rarely threatened after the break, with Leverkusen comfortably holding on to cap a memorable season with a second trophy.

"The most important thing was the belief of the team. They were ready to battle with 10 players and I am proud of that," Alonso added.

"I need time to accept what happened this season. It was a dream season and to celebrate the last day like this here is special."

Long derided as "Neverkusen" for their failure to win a major title since that 1993 cup win, Leverkusen ended their season with more silverware after also winning the Bundesliga title without a single loss -- the first German team to achieve that feat.

"It was a deserved victory," club CEO Fernando Carro said. "We could have added another goal but overall a fully deserved win. We lifted the cup after we failed to do so Wednesday. Compliments to the team to win this double."

Information from Reuters and The Associated Press contributed to this report.