Atalanta stuns Liverpool with second-half flurry
Poland international Lewandowski plundered his 71st goal in the competition shortly before half-time to set Hansi Flick's men on their way to a fourth win out of four and qualification as Group A winner.
A Maximilian Wober own goal doubled their advantage shortly after the restart before Marc Roca was dismissed for a second yellow card in the 66th minute.
Leroy Sane added a third soon after before Mergim Berisha pulled one back for the visitor late on as Bayern moved onto 12 points, seven ahead of second-placed Atletico Madrid with two games remaining.
Serge Gnabry came close to a stunning opener after 10 minutes, but his volley from the edge of the penalty flashed narrowly wide of Cican Stankovic's left-hand post.
Dominik Szoboszlai spurned a glorious opportunity to put the visitors ahead 10 minutes before the interval, the Hungarian blazing wildly over with only Manuel Neuer to beat after being put through by Berisha.
Bayern duly punished him shortly before the interval, Lewandowski slotting home after Stankovic had parried Thomas Muller's effort into his path.
The holder went 2-0 up seven minutes after the restart when Kingsley Coman's low effort from the edge of the penalty area was diverted past Stankovic via the outstretched foot of Wober.
Roca, making just his second start of the season, saw red in the 66th minute after receiving a second caution but Sane added a third two minutes later when he headed home Coman's cross from six yards.
Neuer made a wonderful double save from Berisha and Enock Mwepu before the former scored a 73rd-minute consolation, sliding home Rasmus Kristensen's low cross from close range.
