Ganassi's Dario Franchitti came from nowhere in the earlier Friday practice to claim pole position with his qualifying run - and seemed as surprised as anyone that he'd pulled it off.
"That was cool," Franchitti admitted. "I didn't expect anything like that ... We didn't really have a car that had good balance, that was quick, any of those things.
"That's quite a turnaround from practice. Practice is one thing, qualifying is another - and then there is the race," added the Scot, who is aiming for a second consecutive win on the Milwaukee Mile. "I am very pleased as much as I am surprised."
His two-qualifying lap aggregate time of 43.3100s (168.737mph) was 0.1157s ahead of last week's race winner at Texas, Dale Coyne Racing's Justin Wilson.
"I feel like we've made some progress in understanding this car and what it's looking for, so we'll keep chipping away at it and making the car better and better," said Wilson. "I'm having a lot of fun. Qualifying is great, we'll just keep our heads down, keep working on it."
Wilson said that he was definitely feeling boosted by last week's success - and that he also felt a lot to prove following the team getting penalised for a technical infringement that cast a cloud on his victory.
"The confidence has helped a lot," he said. "We were very pleased with last week. Obviously there was the whole question over the legality, but that's why we've tried to come back and back it up with and we've proved that we're here and we're here to stay."
However, despite setting the second fastest time for the day, Wilson will actually outside the top ten because of a starting grid penalty for an unscheduled engine change post-Texas. Will Power, Scott Dixon, Mike Conway, Takuma Sato, Josef Newgarden and now also Ryan Briscoe all have ten-place starting grid penalties for engine changes since last week's race in Texas.
That leaves Franchitti sharing the front row of the grid with Ryan Hunter-Reay.
"We had a great run," said the Andretti Autosport driver. "The guys did a great job on the car - we were all over the sixth-gear limiter on our last lap - or I think we would have been quick enough for pole. We couldn't have predicted we would be that quick though, it's the quickest we've been all weekend."