Brazilian Helio Castroneves broke the Phoenix International Raceway lap record in posting the fastest time in the IndyCar's first official test day.
Castroneves headed off Penske teammate Will Power, American Marco Andretti and defending series champion - Kiwi Scott Dixon.
"We were able to run in both temperature (conditions), which was OK," Castroneves said. "Obviously, earlier today in the day conditions, we were focusing on speed and the Hitachi car was really dialed in. This evening, we were able to work more on the race pace, and everything seems to be going in the right direction. We're looking strong and looking good, but we're still learning about this updated Chevy aero kit. Looking forward to tomorrow and learning even more."
Testing continues at the track tomorrow.
The season-opening event is at St Petersburg, Florida on March 11-13.