Renault team boss Eric Boullier said Nick Heidfeld made a very strong first impression as he set the quickest time in testing on his debut with the squad at Jerez today.
Heidfeld is the leading candidate to fill in for the injured Robert Kubica at Renault, and did his chances no harm with his pace on his first day in the R31.
"Today we had the chance to give Nick time in the car and we carried out a big evaluation," said Boullier. "Our first feelings are very positive: he worked well with the team, gave good feedback and improved the car during the day."
Boullier said that Vitaly Petrov and Kubica should share the credit for how quickly Heidfeld was able to get on the pace in the Renault.
"We managed to cover 86 laps and the times are encouraging, which is also thanks to Robert and Vitaly's early feedback and the hard work of everybody in the team," he added.
Official Renault reserve driver Bruno Senna will take over from Heidfeld tomorrow but is not a candidate to race for the team at present.