Müller curled in Bayern's fifth as the record champions bounced back in style from their shock 5-0 loss to Borussia Mönchengladbach in the DFB Cup second round.
It was the 33-year-old's 220th competitive goal for Bayern, and means he has now found the net against all of the Bundesliga's 17 other current clubs.
"We won and in the end played a convincing game," reviewed Müller, preferring to deflect attention away from his own match-winning display. "We were dominant in the first half hour and got the goals. We were very happy with that."
Modesty aside, Müller's performance arguably trumped the lot.
Rigged with his patented cloaking device, the Germany international was the catalyst for inflicting a first home Bundesliga defeat on Union in over two years. He touched a free-kick into Robert Lewandowski's feet for Bayern's second, hooked a Kingsley Coman cross into the path of Leroy Sane for their third and sent Coman through on goal for their fourth.
While any player in black and gold could plausibly have assumed the Müller role for Lewandowski's pre-medidated set-piece, his next two deliveries were typical of the atypical Raumdeuter (space interpreter).
An unrivalled hybrid of anticipation, movement and execution, Müller travels back to his native Bavaria with a Bundesliga-leading seven provisions for the campaign and on course retain the assist king crown for the third season in a row.
"Thomas is a very important player for us, a leader with a huge amount of experience," commented Bayern assistant Dino Toppmöller, standing in once more for the unwell Julian Nagelsmann.
"It often comes down to leaders like Thomas in a game like this. Like everyone, he put in a great performance."
The latest in a long line, it should be added.
Müller has produced three single-game assists before, and had a direct hand in four Bundesliga goals on one occasion. All told, Mr. Bayern has registered 133 goals and 176 assists in 393 Bundesliga appearances. That's a goal contribution every 1.21 games.
Ten Bundesliga fixtures into 2021/22 alone, Müller's already on double figures (four goals, seven assists). League-wide, only teammate Lewandowski (12 goals, one assist) boasts a superior combined share.
Shout it from the rooftops because there's scarcely been a more consistent taker and maker of chances in world football than the inimitable Müller. There probably never will be.
Chris Mayer-Lodge