Colton Herta besieged former NTT IndyCar Series champions Will Power and Scott Dixon to take his second series pole at the Grand Prix of Portland at Portland International Raceway.

The Harding Steinbrenner Racing driver's road to the pole began by setting a quick flyer on the black primary tyres before turning a few procedural laps around the 1.964-mile road course.

He upped the ante by ducking in for a set of option red tyres and then turned a blistering 57.8111-second final lap to snatch the pole from Power.

"We didn't have it on the sticker blacks," said Herta. "We always planned to do three and one, and we pulled it off. I think reds were the right choice, I think the second lap could have been a little bit better possibly but nonetheless – everybody did a good job."

Power opted for a much less eventual strtategy by clocking just two flyer laps. A lock-up heading into Turn 1 proved to be the Australian's undoing and ended up .0192s behind to Herta.

Dixon capped off a tepid few practice runs with the third quickest time which put him the quickest of the championship quartet.

Part-timer Jack Harvey made the Fast-Six ended the day in fourth place while his Honda compatriots Felix Rosenqvist and Ryan Hunter-Reay completed the top six.

Alexander Rossi lost out on the Fast Six by just .0277s and ended up seventh. Arrow Schmidt Peterson Motorsports Hondas claimed the next two spots with team stalwart James Hinchcliffe taking eighth in front of interim teammate Conor Daly in ninth.

The Noblesville, Indiana native was drafted by SPM at the last minute as the team's primary driver Marcus Ericsson was called up by the Alfa Romeo team for this weekend's Formula One Grand Prix of Belgium. He will return to Andretti Autosport for the season finale at WeatherTech Raceway Laguna Seca in three weeks.

Completing the top ten was Ed Carpenter Racing's Spencer Pigot ahead of Andretti Autosport sophomore Zach Veach and two-time Portland winner Sebastien Bourdais.

The Team Penske championship duo of Josef Newgarden and Simon Pagenaud find themselves deep in the field after suffering misfortunes during qualifying.

Newgarden pitched a wheel in Turn 8 on his first flying lap before losing control in Turn 6 on his final lap. The lap was momentarily secure before being bumped by Zach Veach at the final second of the opening 10-minute session which knocked him back to an unlucky 13th.

The run still put him ahead of his closest championship rival in Pagenaud, who struggled to find speed and ended up 18th on the grid.