The right back slipped and missed his penalty in the shootout as Jurgen Klopp's men went on to reach the DFB-Pokal final.
Philipp Lahm said he was "extremely bitter" after Bayern Munich lost to Borussia Dortmund on penalties in the DFB-Pokal semifinal Tuesday.
The game finished 1-1 in normal time and neither side could find a winner in extra time at the Allianz Arena, meaning spot kicks were required to decide the winner.
Bayern missed all four of its penalties, with Lahm slipping as he took his effort, leaving Ilkay Gundogan and Sebastian Kehl to convert and send Dortmund through 2-0.