Rene Rast set the early pace with a time of 1m47.482s, but his benchmark was quickly lowered by Robin Frijns, who moved to the top of the timesheets by a tiny margin of 0.021s.
Rast shot back with a time that was two tenths quicker than his previous flyer, and when Frijns was unable to make a major improvement, the reigning champion assumed the provisional pole.
When the second set of runs began, Frijns managed to snatch the top spot again, only for Muller to spoil his party by breaking the 1m47s barrier for the first time this weekend.
The championship leader was trailing in seventh place after the opening runs and was nine tenths off the pace, but his sole lap on his second run was good enough to complete a clean sweep of pole positions at the Nurburgring.
Frijns had to settle for second place, 0.138s down on Muller’s pace-setting lap time of 1m46.958s, but he ensured the Abt Audi team locked out the front row of the grid
Team Rosberg driver Rast could only improve by 0.022s on final run and dropped to third position, while Team Phoenix's Mike Rockenfeller qualified fourth.
Loic Duval finished half a second off the pace in fifth, with Jamie Green - who was third after the first runs - making it six factory Audi drivers in the top six.
Assen Race 2 winner Sheldon van der Linde was BMW’s top qualifier in seventh, 0.761s off the pace, with his stablemate Jonathan Aberdein qualifying just 0.017s adrift in eighth.
Robert Kubica secured his best qualifying result of the season in ninth in the ART-run BMW, beating the factory BMW of two-time champion Marco Wittmann, who rounded out the top 10.
The three WRT Audis propped up the field, with Fabio Scherer setting the 14th fastest time of the session ahead of fellow rookie Harrison Newey and Ferdinand Habsburg, who has joined the customer Audi squad this year after a year with the now-defunct R-Motorsport Aston Martin team.
Nurburgring DTM: Second qualifying results:
|1||51||Nico Müller||Audi RS5 Turbo DTM 2020||1'46.958|
|2||4||Robin Frijns||Audi RS5 Turbo DTM 2020||1'47.096||0.138|
|3||33||René Rast||Audi RS5 Turbo DTM 2020||1'47.203||0.245|
|4||99||Mike Rockenfeller||Audi RS5 Turbo DTM 2020||1'47.400||0.442|
|5||28||Loic Duval||Audi RS5 Turbo DTM 2020||1'47.463||0.505|
|6||53||Jamie Green||Audi RS5 Turbo DTM 2020||1'47.690||0.732|
|7||31||Sheldon Van Der Linde||BMW M4 Turbo DTM 2020||1'47.719||0.761|
|8||27||Jonathan Aberdein||BMW M4 Turbo DTM 2020||1'47.736||0.778|
|9||8||Robert Kubica||BMW M4 Turbo DTM 2020||1'47.861||0.903|
|10||11||Marco Wittmann||BMW M4 Turbo DTM 2020||1'47.862||0.904|
|11||25||Philipp Eng||BMW M4 Turbo DTM 2020||1'47.868||0.910|
|12||16||Timo Glock||BMW M4 Turbo DTM 2020||1'47.880||0.922|
|13||22||Lucas Auer||BMW M4 Turbo DTM 2020||1'48.283||1.325|
|14||13||Fabio Scherer||Audi RS5 Turbo DTM 2020||1'48.453||1.495|
|15||10||Harrison Newey||Audi RS5 Turbo DTM 2020||1'48.580||1.622|
|16||62||Ferdinand Habsburg||Audi RS5 Turbo DTM 2020||1'48.898||1.940|
|View full results|