Scott McLaughlin claimed the pole at World Wide Technology Raceway near St. Louis for the second straight year Friday with a two-lap average of 179.972 mph as Team Penske qualified its three cars in the top five.
"Straight from the truck today the guys gave me a great car," McLaughlin said.
Josef Newgarden qualified fourth and Will Power fifth, but they will start side-by-side in Row 2 for the Saturday night race after a grid penalty knocked Felix Rosenqvist from second to outside the top 10. Rosenqvist's Meyer Shank Racing teammate David Malukas moved up and will start second.
Malukas, who will move to A.J. Foyt Racing next year, also led the opening practice Friday.
"We've been quick on ovals this year, which is great," Meyer Shank Racing co-owner Mike Shank said. "I'm super proud of where we ended up today."
Rosenqvist, Alex Palou, Scott Dixon and Katherine Legge were assessed nine-spot grid penalties Friday for going beyond the permitted number of engines this season. Teams are allowed four motors per entry. The four Honda-powered teams made changes after the last race in Toronto to provide fresh engines for the final five races.
Palou has a 49-point lead in the season standings with three wins and three more podium finishes, putting him in position to win a second straight IndyCar title and third in a four-year span for Chip Ganassi Racing. But the standings are much more bunched behind him with 12 points separating second-place Power from Colton Herta in fourth.
Herta is coming off a win at Toronto, but his team was left repairing his car after he backed into the wall in qualifying.
"Just broke loose. Unfortunate," said Herta, who will start 25th in the 27-car field. "It just let go."
The hottest driver in the series might be Dixon, who is third in points. He has been in the top five in three consecutive races and led in Toronto before finishing third.
Alexander Rossi returned to the track after breaking his thumb during a practice crash in Toronto as IndyCar starts a post-Olympics sprint to the finish for the series.
"It's been a long summer break, but it obviously came at just the right time for me after the injury in Toronto," said Rossi, who will start 13th. "I'm thrilled to be back in the car for St. Louis and looking forward to kicking off this final stretch in a positive way."