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Munich's David Alaba was presented with another decent chance to put the visitors in front soon after, but he produced a comical air-shot with just the keeper to beat.
The league leaders went ahead in the 24th minute thanks to Thomas Muller, who opened the scoring with a curled effort with his left foot.
Alaba managed to atone for his earlier miss right on the stroke of the interval, when he stepped up to curl a standout free kick past Wolf and give Munich a 2-0 lead at the break.
Following a tame start to the second period, Bremen finally sought to test Reina as Davie Selke launched a shot from distance that was smartly kept out by the Spanish stopper.
Bremen were unlucky when Jerome Boateng looked to have brought down Selke in the box, before the ball hit the striker's arm and landed in the Bayern net, only for the referee to give the champions a free kick.
Munich killed the fixture off with just under 15 minutes to play when Lewandowski grabbed his first goal with a classy lob over the keeper.
The Polish international made it 4-0 in the dying embers of the game with a simple finish, after Muller selflessly squared the ball to setup an unmissable chance.