Will Power ended the first day of the IndyCar open test at Barber Motorsports Park on top after setting the fastest time in the afternoon at the Alabama circuit.
Power, who had earlier been the pacesetter in the morning session with a 1m09.8529s, remained the benchmark in the faster afternoon session to finish the day with a best lap of 1m07.8625.
"The cars are unbelievably hooked up here," Power said. "I have never felt so much grip in this car."
Helio Castroneves was 0.07 seconds behind him for a Penske 1-2 at the top of the times, with Andretti's James Hinchcliffe a further 0.04sec back in third.
"It's only the first day of testing, but that [Penske 1-2] shows that we worked hard in the winter," Power added. "As a team we're very determined to check a couple of boxes this year, obviously the Indy 500 and the championship are absolutely top of the list."
Power discounted the impact of the diamond grinding of the track surface as a factor in the fast times.
"The work that was done during the year last year and also engine work with the engine manufacturers, and it's a little cooler, which helps turbo and it helps grip. It's just a very fast situation. You don't really brake here, there's only one place you brake. So it's the cars, the temperature, and remember we're running on black tires. If you can imagine when we put the reds on, it's going to be fast!"
Testing continues at Barber on Wednesday, although the schedule has been revised because of the potential of inclement weather. Sessions are now set from 11 a.m.-1 p.m. and 1:45-6:00 p.m. ET.
Mike Conway finished the day as best of the Honda-powered runners in fourth with a 1m08.1584s for Rahal Letterman Lanigan. The Briton, who will compete at Long Beach in mid-April for the Rahal squad, was behind the wheel of the No. 16 Acorn Stairlifts car and was a consistent front-runner in both sessions.
"Today was about getting comfortable in a car, working with the guys and seeing how they work and getting myself dialed in for Long Beach," Conway said. "I think we got through a lot of stuff, and hopefully helped the guys out for tomorrow. James (Jakes) will be in the car and hopefully he'll like some of the things we got through today and be quick out of the box."
It was the first test of the year for Conway, who worked with engineer Eddie Jones, who also served as his engineer at Andretti Autosport in 2011.
"I'm here to do the best job that I can," Conway said. "It's a new group of people, but some people I've worked with before, so that made it a bit easier. Obviously, I'd like to do a more races, so you have to do a good job whenever you're in the car."
Simona De Silvestro was also a consistent top-10 runner in her new KV Racing Dallara-Chevrolet, winding up sixth overall despite limited running time.
"I think it was a good day. We lost a little bit of time so we didn't get to run that much," related the Swiss. "But I feel like every time we were on the track we made improvements, and that's what counts. I think we can be pretty happy with the day and hopefully we can even make a step more forward tomorrow."
AJ Allmendinger, who will make his open-wheel racing comeback at the Barber race in early April, was 16th fastest on a day where the top 20 times were covered by one second.
"We need as many laps as we can get," Allmendinger conceded, "but my teammates are being great about sharing information to accelerate the learning curve and I am excited to see what we can get done tomorrow."
The five-time Champ Car race-winner's afternoon was not without incident, with eyewitness reporting that his car was sent airborne after going off at Turn 8, although he was able to return to the pits. Even worse off was Sebastien Bourdais, who managed just a handful of slow laps in his Dragon Racing entry.
"Today wasn't the best day as we had some issues with the car causing us to not have much time on track. We've got work to do, some new things to try, and some ground to make," admitted the Frenchman. "Tomorrow we are going to restrict our running time as we do not want to put too many miles on this engine, but we still look to accomplish a lot more than we did today."
Practice 2 times
Tuesday combined session times