Granit Xhaka moved from Arsenal to Bayer Leverkusen in a £21.4m deal last July
Bundesliga champions Bayer Leverkusen completed the Double as they beat Kaiserslautern in the German Cup final, despite playing all of the second half with only 10 men.
Former Arsenal midfielder Granit Xhaka put Xabi Alonso's side ahead after 17 minutes with an excellent curling strike from 25 yards.
However, Leverkusen had defender Odilon Kossounou sent off for two bookable offences, with the second coming just before half-time following a foul on Boris Tomiak.
The second half saw a five-minute delay after supporters in the Kaiserslautern end set off numerous fireworks on a day when the second-tier side were aiming to win the German Cup for the third time in their history - and first since 1996.
Substitute Ragnar Ache had two chances to grab an equaliser and force extra time, but shot narrowly wide from 25 yards and also had an effort parried by Lukas Hradecky.
Leverkusen, who won their first league title and finished 17 points clear of second-placed Stuttgart and 18 in front of Harry Kane's Bayern Munich, had opportunities to score a second in a fantastic atmosphere at the Olympiastadion in Berlin.
Josip Stanisic glanced a header wide and former Celtic wing-back Jeremie Frimpong took the ball around goalkeeper Julian Krahl but was forced wide and could not get a shot away.
But it did not matter as Kaiserslautern could not use their extra-man advantage as Leverkusen won their second German Cup, having last lifted the trophy in 1993.
Alonso's side remained unbeaten through their entire league campaign and had gone 51 matches in all competitions without losing in 2023-24 before being beaten 3-0 by Atalanta in the Europa League final on Wednesday.
Play was delayed at the start of the second half after the Kaiserslautern fans let off a number of flares and fireworks
