New signing Luis Diaz marked his league debut with a goal, Michael Olise grabbed a brace, and Harry Kane delivered a clinical hat-trick to expose Leipzig's defensive woes under new coach Ole Werner.
The match exploded into life after a cautious opening. Bayern's early pressure paid off in the 27th minute when Olise fired home the opener after a loose ball in the box.
Five minutes later, Diaz doubled the lead on his Bundesliga bow, smashing a shot off the underside of the crossbar from Serge Gnabry's clever lay-off. Olise then made it three before halftime in the 42nd minute, slotting coolly past Peter Gulacsi after another assist from Gnabry.
Leipzig, who are adjusting to life under Werner following his summer arrival from Werder Bremen, looked shell-shocked. Werner has said the team need time to gel, but their backline crumbled under Bayern's fluid attacks. Willi Orban's heavy foul in the 34th minute earned a yellow card and highlighted their struggles, though he escaped a red.
At the break, Werner rang the changes, introducing Antonio Nusa and Romulo for Yan Diomande and Lois Openda. The substitutes sparked a brief revival, Nusa had a goal disallowed in the 66th minute for an irregular free-kick in the build-up, and earlier missed a golden chance after Dayot Upamecano's error. Nicolas Seiwald also squandered an opportunity set up by Xaver Schlager.
But Bayern were unforgiving on the counter. Kane struck first in the 64th minute, cutting inside and firing low past Gulacsi after a pass from Diaz.
The Englishman then unleashed a powerful long-range effort for his second in the 74th minute, before completing his hat-trick three minutes later with a left-footed finish.
Kane has now scored three or more goals in a single Bundesliga game on eight occasions in his career with Bayern.
Vincent Kompany's side introduced young talent Lennart Karl late on, giving fans a glimpse of the future amid their injury concerns, Leon Goretzka battled through an early ankle twist.
For Diaz, the Colombian who joined from Liverpool in a deal worth 75 million euros just weeks ago, it was a dream start. He has said the move was "a big gamble" but expressed gratitude to Bayern's management for "reaching out to me and trusting me."
Diaz also spoke of consulting former Liverpool teammate Florian Wirtz about the Bundesliga's physicality, adding: "I hope to have a great debut. I've been here at the club for about two weeks, and I need time to settle in."
Leipzig captain David Raum summed up their nightmare, calling it "a disaster not just for me, but for the entire team." Bayern's dominant display sends a clear warning to rivals, they are primed to retain their crown.