The Spaniard admitted that his side were not at their best against their second-tier opponents, but was quick to praise their fighting spirit.
"Kaiserslautern were very courageous from the start," Guardiola told reporters. "We had problems with our possession of the ball.
"It's never easy to score five goals, regardless of the opponents or the competition you're playing in. I am happy about how we fought. I am looking forward to playing in the final."
Bayern will meet arch rivals Borussia Dortmund in the final.