Bayern crushed the Spaniards last week in a surprisingly one-sided encounter but Beckenbauer, former player, coach and president of Germany's most successful club, warned that Barcelona were not ready to surrender.
"Barca will try everything to throw Bayern off balance," he told Bild newspaper. "They will deploy all methods, anything that's allowed and anything that's forbidden. They will defend themselves because their pride has been hurt."
Bayern, leading 1-0 at half-time, played a flawless second half against the former European champions - widely considered the best team in the past five years - last week in Munich to notch up another three goals and take a huge advantage into the second leg in Spain.
"Barca will try to take Bayern's eyes off their game plan with one-on-one duels. The Bayern players should not be drawn into personal battles," said the 67-year-old Beckenbauer who won three consecutive European Cups with Bayern in the 1970s.
"They will not surrender, they will provoke, they will try all the tricks in the book.".
Bayern, who have already won the Bundesliga and are in the German Cup final, are bidding for an unprecedented treble of titles for a German club.
The Bavarians are also aiming for their third Champions League final in four seasons after losing the 2010 and 2012 finals to Inter Milan and Chelsea respectively.
