Andrej Kramaric scored the only goal after 21 minutes Tuesday to check the progress of the Bundesliga's champions-elect, while further strengthening Hoffenheim's improbable bid for Champions League football next season.
The team that 29-year-old coaching protege Nagelsmann saved from relegation with seven wins from their final 14 matches last term lie third, a point above Borussia Dortmund and 11 clear of fifth-place Cologne with seven matches to play.
Hoffenheim have taken four points off Bayern, having left the Allianz Arena with a 1-1 draw earlier in the campaign, and Nagelsmann compared their success to a recreational activity of which he was quick to point out he has no first-hand experience.
"To win is like a drug. I never tried drugs but I imagine a drug noise to be like that," he told Bild.
"After one minute 20 [seconds] you could see our plan. I thought, 'It's not possible that out plan works that well'. It's mad."
Nagelsmann was in the mood for further analogies, while explaining his tactical schemes owe something to quality time spent alone.
"I have my best ideas in the bathroom," he explained. "After it I paint my idea on a paper with a ruler and a lead pencil.
"I work like a baker. I mix things, shove them in the oven and see if it tastes well."
Hoffenheim's next test of whether their highly touted boss has the right ingredients comes when they travel to Hamburg on Saturday, chasing a fourth consecutive Bundesliga win.