McLaughlin’s 1:07.6325s with just over a minute remaining in the 75-minute session left the New Zealander 0.0991s ahead of Andretti Global’s Colton Herta.

Chip Ganassi Racing’s Alex Palou ended up third, from fellow two-time IndyCar champion Josef Newgarden, with another two-time champ and last-start race winner Will Power 10th-quickest.

CGR’s Linus Lundqvist (#8 Honda) was the early pace-setter, lapping as quickly as a 1:09.2218s as the rookies ran on their own on their extra tyres.

Rahal Letterman Lanigan’s Graham Rahal (#15 Honda) was first to knock him off, with a 1:09.0374s in the 24th minute, as Newgarden sat in pit lane with what was said by Team Penske to be an issue with the exhaust pipe on the #2 Chevrolet.

A red flag came moments later when David Malukas (#66 Meyer Shank Racing Honda) spun and stalled at the Andretti Hairpin, requiring the recovery crew to attend to him despite staying away from the gravel.

With 33 minutes on the clock, there was a relative flurry as Andretti’s Kyle Kirkwood (#27 Honda) set a new fastest lap of 1:08.6421s, before Pato O’Ward (#5 McLaren Chevrolet), Rinus VeeKay (#31 Ed Carpenter Racing Chevrolet), and then Romain Grosjean (#77 Juncos Hollinger Racing Chevrolet) moved into second place.

Grosjean was back to third once Palou (#10 Honda) moved the benchmark to a 1:08.5664s next time through.

Santino Ferrucci was only 20th but attracted attention when he spun at The Corkscrew, then let the #14 AJ Foyt Racing Chevrolet roll down through those corners in order to clear the area.

A second red flag was called with 25 minutes remaining when O’Ward ran off at Turn 5, prompting Kirkwood and Marcus Ericsson (#60 MSR Honda) to switch to alternate compound tyres.

Unsurprisingly, Ericsson moved to the top on a 1:08.2347s and Kirkwood reclaimed second place on a 1:08.3524s with just over a quarter of an hour remaining.

More moved to the ‘reds’ and Newgarden claimed the ascendancy with a 1:08.1587s, backing it up two laps later with a 1:07.8805s.

As the session wore into its final 10 minutes, Herta wheeled the #26 Andretti w/ Curb-Agajanian Honda to a 1:07.7316s.

With just over a minute to go, McLaughlin knocked him off with a 1:07.6325s in the #3 Penske Chevrolet and that would be the fastest lap of the session all-told.

The rest of the top 10 was Herta in second, from Palou, Newgarden, Pietro Fittipaldi (#30 RLL Honda), O’Ward, Kirkwood, Alexander Rossi (#7 McLaren Chevrolet), Marcus Armstrong (#11 CGR Honda), and Power, with Scott Dixon (#9 CGR Honda) 18th at 0.8476s off the pace.

Practice 2 starts on Saturday at 13:00 ET/Sunday at 03:00 AEST, followed by Qualifying from 17:15 ET/07:15 AEST.

Results: Practice 1