The Germany legend expressed his excitement at the prospect of seeing the Pole at the Allianz Arena next season, even if it's at the expense of the current No.9
The Poland international has already signed a deal with the Bundesliga champions and will move to the Allianz Arena from Borussia Dortmund on a free transfer this summer.
And Beckenbauer, an honorary president for the Bavarians, believes Lewandowski will play a starring role at for Pep Guardiola's side, suggesting he is a better fit than Mandzukic.
When asked by 11 Freunde magazine if Lewandowski will make the Croat "pack his bags", the Germany icon replied: "Yes. I assume that Lewandowski will be an immediate hit.
"His style fits Guardiola's tactics better than a pure box striker like Mandzukic. Plus, Pep could also put Thomas Muller or Mario Gotze up front."
Beckenbauer also reflected on the superiority that Bayern have shown in the last 18 months and believes it will continue for many seasons to come if they can keep adding world-class players to their squad.
"They are very hard to beat, no doubt about it," the 68-year-old mused. "Especially if they keep reinforcing like they do. And they will.
"Pep Guardiola is the perfect coach and Matthias Sammer wakes them up if they're too relaxed. There is enough competition within the squad so they can be successful in all competitions. I do not see why that should change in the coming years."
Bayern return to Bundesliga action on Friday away to third-placed Borussia Monchengladbach.