Honda hopeful Lucas di Grassi put forward his case for a race seat in 2009 by getting to within half a second of regular pilot Jenson Button on day two of the current Barcelona group test, admitting that he had taken a big step forward overnight.
Having had to split the opening day with fellow aspirant Bruno Senna, the Brazilian got a full day in the second RA108 as Honda continued to run the rule over potential partners for Button next season and, after an installation run, completed a back-to-back balance evaluation on used slick tyres from Jenson's programme before the team fitted new rubber for his final run of the morning.
In the afternoon session, di Grassi - who finished third, just behind Senna, in the GP2 Series standings - used two further sets of new Bridgestones as he worked though a chassis set-up programme, improving his lap time as he gained confidence in the car.
"I completed 110 laps, so I have had a really productive day and I am very pleased," the former Renault F1 development driver noted, "I ran for the first time, properly, with new tyres and the difference was massive compared to the used tyres from yesterday.
"With each new tyre run, I was getting faster and faster. The slick tyre has much more grip and, compared with the grooved tyre, is easier to drive and more consistent over a run, so I was very pleased with the performance of the car, the way the day developed and, ultimately, my lap time.
"I ended the day 0.5secs from Jenson's time and getting as close to him as possible was my target. I don't think the day could have gone much better. I felt like I gave everything I could."
Button, meanwhile, joined the test for the first time, taking over from test driver Alex Wurz. After adjusting the set-up of the car to his liking, the Briton concentrated on a tyre programme using the latest Bridgestone slicks to run through various set-up and balance changes. The Briton will continue for a second day today [Wednesday], when he will be joined by Senna, who gets his full day behind the wheel as part of the team's evaluation programme.