The newly-crowned Bundesliga champions eventually ran out 6-1 winners to reach the final of the German domestic cup, but the Swiss playmaker felt that the impending Barca match threatened to overshadow the game.
Shaqiri told reporters after the game: "We wanted to reach the cup final but it was difficult for us.
"All talk about Barcelona had made it hard to concentrate. But we did it and had the game under control."
The result leaves Die Roten on course to win a historic Treble this season, which is something that defender Javi Martinez admits the club should try to play down.
"It is impossible not to talk about the Treble but we do not want to think about it," the Spaniard told Marca.
The Bavarians host Barca on April 23 at the Allianz Arena, with the return leg on May 1 at Camp Nou.