McLaughlin, a rank outsider in the points race with a 54-point deficit to Power heading into the final two races, pipped Newgarden by 0.078s in the decisive Fast Six session to secure the top spot - although a six-place grid penalty for Newgarden's engine change will drop him to eighth on the grid.
Points leader Power will therefore line up on the front row of the grid, with impressive rookie Christian Lundgaard lining up third for Rahal Letterman Lanigan Racing ahead of defending champion and 2021 Portland winner Alex Palou in the leading Chip Ganassi Racing entry.
Palou, 43 points down on Power and fifth in the standings, fared much better than his team-mates who are also in the thick of the title fight. Scott Dixon (14 adrift) and Marcus Ericsson (17 adrift) will start down in 16th and 18th respectively, after managing the eighth and ninth quickest times in their Q1 group.
Lundgaard initially set the benchmark of 58.448s in the Fast Six pole shootout, which neither Newgarden or McLaughlin could match on their first flyers.
Power then went quickest, albeit briefly as he had accidentally shifted up in Turn 4 while adjusting his front anti-rollbar. McLaughlin and Newgarden then both usurped the Australian, who ended up 0.112s shy of McLaughlin's pole lap.
Palou couldn't deny Lundgaard the honour of best non-Penske driver, while Pato O’Ward in the top Arrow McLaren SP entry was the slowest driver in the Fast Six but will line up fifth alongside team-mate Felix Rosenqvist.
The Swede narrowly missed out on a place in the Fast Six after lapping just 0.009s slower than sixth-placed Palou in Q2.
There, Newgarden had gone fastest with a 57.965s quicker than McLaughlin's eventual pole time ahead of Lundgaard, Power and McLaughlin.
Behind Rosenqvist, eighth represented a good result for Colton Herta after he'd tapped the Turn 1 wall during his Q1 group and required a quick repair to his right-front suspension from his Andretti Autosport team to ensure he progressed.
The American, who has been linked with an AlphaTauri Formula 1 berth if Pierre Gasly moves to Alpine, was the highest-placed AA driver ahead of team-mate Alexander Rossi.
Lundgaard's rookie of the year rival David Malukas took tenth spot for Dale Coyne Racing ahead of Graham Rahal in the second RLL machine and Rinus VeeKay's Ed Carpenter car.
Takuma Sato, a winner at Portland in 2018 for Rahal, will start 22nd in the second DCR entry.
IndyCar Portland Fast Six Qualifying Results
| Cla | Driver | Team | Time | Gap |
|---|---|---|---|---|
| 1 |  Scott McLaughlin |
 Team Penske |
58.2349 | |
| 2 | Josef Newgarden |
Team Penske |
58.3129 | 0.0780 |
| 3 |  Will Power |
Team Penske |
58.4254 | 0.1905 |
| 4 |  Christian Lundgaard |
Rahal Letterman Lanigan Racing |
58.4482 | 0.2133 |
| 5 |  Alex Palou |
Chip Ganassi Racing |
58.5075 | 0.2726 |
| 6 |  Patricio O'Ward |
Arrow McLaren SP |
58.6090 | 0.3741 |
| View full results | ||||
