The #3 Chevrolet was 10th in the morning session with a 20.8786s but was only 23rd in the afternoon on a 21.5055s.

Still, it marked a day-on-day improvement for McLaughlin, whose best lap on Wednesday was a 21.1227s.

“I was a bit disappointed in the overall speed with the Chevy following the first day of the test,” said McLaughlin.

“We came back today and tuned it up. I felt really comfortable and competitive today, and ready to come back for the IndyCar-NASCAR doubleheader weekend.

“The conditions were windy and cold today so that will give us something to think about before we come back, but I’m confident that we will get it all dialled in.”

Ed Carpenter Racing’s Alexander Rossi was quickest across both sessions on Thursday, clocking a 20.6370s before slightly improving his benchmark to a 20.6254s.

“We got through everything we wanted, and when you can do that, it’s a good day,” Rossi said.

“Christian’s (Rasmussen) car is also strong, so there’s nothing more I could ask for.

“We have a good baseline, and it feels like we are on top of it.”

On combined times, Josef Newgarden (Team Penske) was second, Alex Palou third (Chip Ganassi Racing), Christian Rasmussen (Ed Carpenter Racing) fourth, and David Malukas fifth (Team Penske).

“It was great to be back at Phoenix,” said Newgarden.

“I have a lot of fond memories of this place from the last race in 2018 when we ended up in victory lane.

“Hopefully we can have the same success at the doubleheader weekend coming up, which will be an amazing weekend of motorsports.

“And we actually have several crew members from 2018 so we know we can get it done, even if it is a new configuration.

“It’s a blast to race on, for sure and the Chevy had plenty of speed.”

All but one driver, Sting Ray Robb, improved on their Wednesday benchmark.

Will Power was eighth for Andretti Global, continuing a solid start for the Honda-powered driver with the most laps – 259 in total – of any driver.

Teammate Kyle Kirkwood was just ahead of him in seventh while Marcus Ericsson was just behind in ninth. The Indianapolis 500 winner ended the day in the wall after spinning.

Results: IndyCar Series Unser Open Test Day 2, Phoenix Raceway