Muller held the top spot for much of the 20-minute pole-shootout in Portugal, grabbing an early edge over his rivals with a time of 1m40.137s in his Audi R8 LMS GT3.
Red Bull driver Felipe Fraga briefly deposed Muller with a 1m40.001s flier as the second runs began, highlighting the one-lap pace of his AF Corse-run Ferrari 488 GT3 for the second day in succession.
However, it took little time for Muller to regain the initiative, the factory Audi driver setting a blistering time of 1m39.974s on his next flying lap to secure his first pole in the DTM's GT3 era.
Bortolotti again opted to complete only a single run in qualifying and jumped to second late on, although the factory Lamborghini driver’s time was slower than his pole-setting lap from Saturday, leaving him two tenths behind Muller in the timesheets.
Brazilian racer Fraga was shuffled down to third in the final order, albeit just 0.010s behind Bortolotti, while Sheldon van der Linde finished another 0.001s adrift in fourth in his Schubert Motorsport BMW M4.
Saturday race winner Lucas Auer was Mercedes’ top qualifier in fifth, setting a time of 1m40.055s in his Winward AMG GT3 ahead of the similar machine of HRT driver Luca Stolz - who coincidentally finished second behind Auer in the opening race of the weekend.
Auer will carry 25kg of additional weight on his Mercedes in the race as part of the DTM’s updated success ballast rules, with Stolz and Bortolotti hobbled by 15kg and 5kg in extra weight respectively.
Two-time DTM champion Marco Wittmann put on a much stronger performance in qualifying on Sunday, putting his Walkenhorst BMW seventh on the grid ahead of Abt Sportsline Audi duo Kelvin van der Linde and Ricardo Feller.
The top 10 was rounded out by reigning champion Maximilian Gotz, who has switched to the Winward Mercedes team this year after winning the 2021 title with Hubert Haupt’s HRT outfit.
SSR Performance’s Laurens Vanthoor was the top Porsche driver on the grid in 11th in an ultra-competitive session where 15 out of 29 drivers were separated by just half a second, and the entire field but Alessio Deledda separated by two seconds.
After retiring from Saturday’s race due to contact at the restart, Abt Audi DTM star Rene Rast qualified 13th with a time of 1m40.283s, just fractionally ahead of the slowest Audi of Attempto driver Marius Zug.
Nicki Thiim, who qualified fifth on his DTM debut on Saturday, struggled for pace on Sunday and ended up a distant 20th on the grid in his T3 Motorsport Lamborghini.
Nine-time World Rally champion Sebastien Loeb was also unable to replicate his pace from Saturday and will line up 27th on the grid in his AlphaTauri-sponsored AF Corse Ferrari, only ahead of the Lamborghinis of Esmee Hawkey and Deledda.
Portimao DTM - Sunday qualifying results:
| Cla | Nº | Driver | Car | Time | Delay |
|---|---|---|---|---|---|
| 1 | 51 | Nico Müller | Audi | 1'39.794 | |
| 2 | 63 | Mirko Bortolotti | Lamborghini | 1'40.001 | 0.207 |
| 3 | 74 | Felipe Fraga | Ferrari | 1'40.011 | 0.217 |
| 4 | 31 | S.van der Linde | BMW | 1'40.012 | 0.218 |
| 5 | 22 | Lucas Auer | Mercedes | 1'40.055 | 0.261 |
| 6 | 4 | Luca Stolz | Mercedes | 1'40.063 | 0.269 |
| 7 | 11 | Marco Wittmann | BMW | 1'40.107 | 0.313 |
| 8 | 3 | K.van der Linde | Audi | 1'40.153 | 0.359 |
| 9 | 7 | Ricardo Feller | Audi | 1'40.154 | 0.360 |
| 10 | 1 | Maximilian Götz | Mercedes | 1'40.189 | 0.395 |
| 11 | 92 | Laurens Vanthoor | Porsche | 1'40.210 | 0.416 |
| 12 | 12 | Dev Gore | Audi | 1'40.236 | 0.442 |
| 13 | 33 | René Rast | Audi | 1'40.283 | 0.489 |
| 14 | 66 | Marius Zug | Audi | 1'40.285 | 0.491 |
| 15 | 55 | Mikaël Grenier | Mercedes | 1'40.304 | 0.510 |
| 16 | 94 | Dennis Olsen | Porsche | 1'40.378 | 0.584 |
| 17 | 10 | Esteban Muth | BMW | 1'40.410 | 0.616 |
| 18 | 88 | Maro Engel | Mercedes | 1'40.471 | 0.677 |
| 19 | 25 | Philipp Eng | BMW | 1'40.537 | 0.743 |
| 20 | 95 | Nicki Thiim | Lamborghini | 1'40.563 | 0.769 |
| 21 | 24 | Thomas Preining | Porsche | 1'40.580 | 0.786 |
| 22 | 36 | Arjun Maini | Mercedes | 1'40.597 | 0.803 |
| 23 | 18 | Maximilian Buhk | Mercedes | 1'40.622 | 0.828 |
| 24 | 27 | David Schumacher | Mercedes | 1'40.670 | 0.876 |
| 25 | 85 | Clemens Schmid | Lamborghini | 1'40.947 | 1.153 |
| 26 | 19 | Rolf Ineichen | Lamborghini | 1'40.959 | 1.165 |
| 27 | 37 | Sébastien Loeb | Ferrari | 1'41.045 | 1.251 |
| 28 | 26 | Esmee Hawkey | Lamborghini | 1'41.613 | 1.819 |
| 29 | 6 | Alessio Deledda | Lamborghini | 1'42.208 | 2.414 |
