Atlético have won four and drawn one of their last five matches, scoring seven goals, conceding one and keeping four clean sheets.
The run stretches to nine games unbeaten in all competitions, and it includes 1-0 and 2-0 wins at Espanyol and Levante and a 1-0 home win over Deportivo.
At the Metropolitano the hosts have scored 13 and conceded three in six matches across LaLiga and the Champions League.
In Europe they lost 2-1 at Liverpool, then beat Manchester United 2-0 and held Stuttgart to a 1-1 draw while playing with 10 men from the 64th minute, after the red card shown to Morten Hjulmand.
Bayern have won three and drawn two of their last five, scoring 19 and conceding seven without a clean sheet, including 6-1 wins over Leipzig and Magdeburg.
They are unbeaten in 19 games in all competitions, yet they have conceded in each of their last seven, most recently in the 2-2 draw with Dortmund on Saturday.
In the league phase Bayern beat Bodø/Glimt 5-0, drew 3-3 at Viking, where Michael Olise was sent off, and drew 2-2 with Arsenal.
Their attack travels less well than it scores at home, with 27 goals in six matches in Munich against 10 in five away, or two per game.
That drop matters in Madrid, where Atlético have scored only four times in three Champions League games and will need more cutting edge against a defence that has let in five in the same competition.
The two clubs have met eight times, with Bayern winning four, Atlético two and two matches drawn.
The latest meeting was a 1-1 draw in Madrid on December 1, 2020, six weeks after Bayern won 4-0 at home, so the record is only background for this tie.
Atlético won the 2015/16 semi-final first leg 1-0 at home, lost 2-1 in Munich and went through on the away goal, and each side then won 1-0 at home in 2016/17.
Bayern have never won in Spain against Atlético, with no win in three attempts, a record that rests on matches played nearly six years ago or longer.
