Kaiser: Inconsistent Bayern just like Liverpool
The Germans are unbeaten in this season's Champions League but their form has been inconsistent in the Bundesliga.
Liverpool, who have not lifted their domestic title in almost two decades, won Europe's top club competition in 2005 and were beaten in the final two years later. On Tuesday, the Anfield team notched a 5-0 aggregate victory over Real Madrid.
"Maybe Bayern are becoming a bit like Liverpool," Beckenbauer told DSF television after his side crushed Sporting 7-1 in the second leg at the Allianz Arena.
"The players clearly enjoy playing in the Champions League which they see as a special challenge."
Lukas Podolski led the Bayern spree with two goals. Bastian Schweinsteiger, Mark van Bommel, Miroslav Klose (penalty) and Thomas Mueller also struck while Sporting defender Anderson Polga put through his own net.
Coach Jurgen Klinsmann, who has come under fire for Bayern's up-and-down Bundesliga title challenge, said it was time for his players to focus hard on wiping out their four-point deficit on leaders Hertha Berlin.
"The Bundesliga is a bit difficult this season given the team won the (domestic) double last year," said Klinsmann.
"My team enjoys the Champions League but we must now turn our eyes to the league."
Bayern have lost three times in the Bundesliga since the turn of the year and have also been knocked out of the German Cup.
Beckenbauer warned his players to improve their domestic form.
"If we don't watch out at home maybe there is no Champions League to play in next season," he said.