Ideal conditions and a full day of almost completely trouble-free running meant that teams and drivers managed to get the most out of the first of the two-day testing opportunity at the 4.428km Circuito de Jerez.
Fabio Leimer was particularly happy with his first day testing for Racing Engineering, which saw him set the fastest time of the day and top both the morning and afternoon sessions.
"Today was very good," he said. "I think we worked together really well and I also know now where I still have to improve my driving - I am looking forward to tomorrow's test day and hope we can repeat today's results."
It wasn't all plain sailing for the Swiss driver, however. "In the morning it was difficult to say as all went out on new tyres, and for me it was important to get to know the track and also get used to a new car. Then we could actually start to work on the car and made some positive steps forward.
"These were translated into results and we were able to set the fastest time. From there we simply continued our work and I am glad we were underlining this by also marking the fastest lap time in the afternoon session."
Running in the second Racing Engineering car, Rodolfo Gonzalez was almost a second back from Leimer but felt he'd made a lot of advances. "I'm quite happy with the team work. They helped me to progress a lot during the day and we made important steps to go forward. Now it's down to keeping up this work. I feel that I did a great step in my driving today."
Leimer will continue to helm the car on Thursday, while Gonzalez will make way for British driver Rupert Svendsen-Cook.
Scuderia Coloni finished in second place in the morning session, thanks to the current GP2 "vice-champion" Luca Filippi recording a time of less than a hundredth of a second slower than Leimer's best of the day.
"As soon as I got on track I felt that I was driving the same perfect car that allowed me to win in Monza, so the laptime came easily and could have been even better," he said afterwards. "Apart from this, we also did a good job on the technical side, trying some solutions that came to our mind during the season. It was really a great session, we are very happy with it."
He ceded the car to Kevin Ceccon for the afternoon session, who explained that speeds weren't his aim on Wednesday. "Driving in the afternoon and with a lot of fuel I wasn't really looking for performance today. My aim was trying a lot of different set-ups with the team, something you never really get the chance to do during the season."