Di Resta completed 89 laps of the Jerez circuit on the opening day of testing.
"A positive first day and we managed to cover lots of laps – so that’s the most important thing," he said.
"I felt very comfortable all day and we managed to get through the programme as we focussed on collecting aero data and understanding how well the car correlates with our simulation tools at the factory. We also started trying to learn as much about the tyres as possible so that we can carry that into tomorrow and optimise the set-up. The new compounds are quite different with the new construction and I’ve already felt a difference with the balance of the car in the low and high speed parts of the lap."
"In the morning we focused on aero data collection before moving to baseline set-up work just before lunch," added chief race engineer Jakob Andreasen. "For the afternoon Paul completed some longer runs as we started to get an understanding for the 2013 tyres, especially the medium compound, and how they perform."