Rubens Barrichello got his first taste of the new Williams at Valencia on Monday, and despite a small problem with the throttle was happy with his day at the wheel of the Cosworth-powered FW32.
Barrichello, who made his F1 debut with Jordan way back in 1993, completed 75 laps in total and while his best - a 1 minute 14.449 seconds - was around two seconds off the pace-setting Ferrari of Felipe Massa, the Brazilian wasn't concerned.
"You can't predict anything from the times today; and probably won't be able to for the remainder of the tests because of the fuel loads people will run with such big tanks. It probably won't be until Bahrain qualifying that we will see where everyone is," said Barrichello.
"We are working on improving the balance of the car. It's running reliably, despite the small issue with the throttle. As everything is new, it was a good day. I enjoyed it - it was like a first day at school!"
Williams technical director Sam Michael meanwhile was also upbeat and he was satisfied with the days work which focused mainly on initial systems, performance and reliability checks.
"It was a productive first day testing, with the car completing 75 laps in total. Considering everything is new, in particular the Cosworth engine installation, it was good to get through the day without any major problems.
"We did have a minor software issue with the throttle control towards the end of the session, but that is easily sorted out for tomorrow [Tuesday]. We are well underway with set-up work now and tuning the FW32 around the new Bridgestone tyres," Michael summed-up.