Josef Newgarden took his eighth career pole for the IndyCar round at Gateway, while title rival Alexander Rossi will start the race from 11th on the grid.
Newgarden, who was champion for Team Penske-Chevrolet in 2017 - winning that season's Gateway round - set a two-lap average of 186.508mph to beat the provisional pole time set by Sebastien Bourdais of Dale Coyne Racingby just under 0.6mph.
Several drivers had been annoyed by the speed-dry cement which had been thrown down in Turns 1 and 2 to soak up oil from the vintage Indycars that had been lapping in a demonstration in the previous hour, but both Bourdais and his teammate Santino Ferrucci appeared largely untroubled.
Will Power, defending Gateway winner, and Simon Pagenaud will start the race from third and fourth respectively, while Rahal Letterman Lanigan Racing-Honda's Takuma Sato clocked fifth fastest.
Ferrucci supplemented Bourdais' performance with sixth on the grid.
Arrow Schmidt Peterson Motorsports' James Hinchcliffe bounced back from a poor practice session, admitting he used rookie teammate Marcus Ericsson's setup to land a strong P7.
Scott Dixon felt his Chip Ganassi Racing setup took too long to work his tires up to temperature and was disappointed with eighth, two spots ahead of rookie teammate Felix Rosenqvist.
The pair were separated by the fastest of the Andretti Autosport-Honda drivers, Ryan Hunter-Reay, but Rossi, now 36 points behind Newgarden after the Pocono shunt last week, will start only 11th, alongside semi-teammate Colton Herta.
Graham Rahal had a wild moment on the cement dust and had to back off, which explains why he is down in 16th while Marco Andretti had an even worse moment, forcing him to back off the throttle to keep his car off the Turn 2 wall, and so will have to start at the back.
|1||Josef Newgarden||Team Penske||Dallara/Chevrolet||186.508|
|2||Sebastien Bourdais||Dale Coyne Racing||Dallara/Honda||185.927|
|3||Will Power||Team Penske||Dallara/Chevrolet||185.896|
|4||Simon Pagenaud||Team Penske||Dallara/Chevrolet||185.143|
|5||Takuma Sato||Rahal Letterman Lanigan||Dallara/Honda||185.050|
|6||Santino Ferrucci||Dale Coyne Racing||Dallara/Honda||184.830|
|7||James Hinchcliffe||Schmidt Peterson Motorsports||Dallara/Honda||184.452|
|8||Scott Dixon||Chip Ganassi Racing||Dallara/Honda||184.293|
|9||Ryan Hunter-Reay||Andretti Autosport||Dallara/Honda||184.206|
|10||Felix Rosenqvist||Chip Ganassi Racing||Dallara/Honda||184.130|
|11||Alexander Rossi||Andretti Autosport||Dallara/Honda||184.070|
|12||Colton Herta||Harding Racing||Dallara/Honda||183.399|
|13||Spencer Pigot||Ed Carpenter Racing||Dallara/Chevrolet||183.211|
|14||Marcus Ericsson||Schmidt Peterson Motorsports||Dallara/Honda||183.180|
|15||Zach Veach||Andretti Autosport||Dallara/Honda||182.547|
|16||Graham Rahal||Rahal Letterman Lanigan||Dallara/Honda||182.065|
|17||Ed Carpenter||Ed Carpenter Racing||Dallara/Chevrolet||181.334|
|20||Tony Kanaan||AJ Foyt Enterprises||Dallara/Chevrolet||178.974|
|21||Matheus Leist||AJ Foyt Enterprises||Dallara/Chevrolet||178.290|
|22||Marco Andretti||Andretti Herta||Dallara/Honda||175.192|
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