Simon Pagenaud topped first practice at Long Beach in a highly competitive session in California ahead of Alexander Rossi and Scott McLaughlin.
Pagenaud set a blistering 1:07.1991 for Meyer Shank Racing and went four-tenths quicker than his nearest rival, the 2016 Indy 500 winner Rossi.
The reigning champion Alex Palou finished in seventh place at the track where he clinched the title in 2021.
Pagenaud spoke to media after practice including Motorlat, after practice about how important both tire and track temperatures will be over the weekend.
“A lot of it is how the tires will suit the track and how hot the track is,” Pagenaud said.
“When it’s colder, the tire doesn’t overheat and produces more grip for you.
“The downforce also works better. The worst cars tomorrow are going to get better, and it’s going to level up the field, basically.
“The fastest car is still going to be fast, but the margin will not be as much. You have to expect that.
“With the temperature change, we know what aerodynamical change we need to make on the front wing versus the rear wing. Simulation programs these days really help for these conditions.
“It’s amazing the technology that goes into it and how much we can trust it.”
Palou was astounded by the vast amount of grip the circuit had at this early stage of the weekend. He said: “We were all surprised by the level of grip we had already.
“On the first timing lap, we were doing 69 (1:09), 68 (1:08). It was really grippy. I don’t know if it’s all the rubber from the tires from the other series or just the heat, but it’s super nice to drive. We’re enjoying every lap.”
British driver Callum Ilott continued his admirable start to the campaign for Juncos Hollinger Racing finishing in P9 and topped the rookie class on the 1.968 mile circuit.
The 23-year-old set a 1:08.0201 and accumulated the most laps in the 45-minute session with 23 laps.
He spoke after first practice about his solid start to the weekend: “Yeah, obviously a great start to the weekend. We had a lot of items to test.
“This is one of the tracks I'd been at last year. It made sense to put the most items to test on the weekend here. I got through all of that obviously with a good result as well.”
The first practice session of the weekend also wasn’t without disruption. A red flag occurred 27 minutes into the session as Jimmie Johnson crashed at Turn 5.
He injured his right hand in the crash and said after the session: “As you can see, I’m a little banged up here and have a splint on.
"First and foremost, apologies to the fans at the autograph session I wasn’t able to attend. Clearly I’ve got something else going on here.
“I’m on my way to be further evaluated just to get a good honest look and understand what my options are. I really don’t have any clarity at this point. And I look forward to updating you all very soon.”
Dalton Kellett also spun at Turn 5 causing a red flag in his A. J. Foyt Enterprises car.
Jimmie Johnson and Kellett finished the opening session of the weekend session in P18 and P24.