Kane double fires Bayern into Club World Cup last eight
Vincent Kompany's side will now play European champions Paris Saint-Germain in Atlanta on Saturday for a place in the last four.
Flamengo, backed by a huge and passionate following at Hard Rock Stadium, bow out of the tournament despite a performance of real determination from Filipe Luis's team.
It took just six minutes for Bayern to grab the lead when Joshua Kimmich whipped in a corner and Flamengo defender Erick Pulgar's header flashed into his own net off the far post.
Four minutes later and Bayern had doubled their advantage.