Marco Sorensen topped the second day of Formula Renault 3.5 testing at Barcelona on Wednesday.
The Dane, who finished sixth in the series for Lotus this season, stayed with the team for the two-day test. His best time of the day came in the morning session, when track conditions were better and all but one of the 25 runners set their fastest times.
"I ended the season with a retirement so it's been a real boost for me to have two days of testing straight away," said Sorensen. "In my head I'm already in 2013, and the aim is to compete in Formula Renault 3.5 again. Over these two days we've been able to identify what had been bothering us in the last few races."
GP2 race winner Marcus Ericsson was just 0.01sec adrift of Sorensen's best in second place, while Arthur Pic completed a promising first test for new team AV Formula by going third quickest overall, and leading the way in the slower afternoon session.
British F3 racers Carlos Sainz Jr. and Jazeman Jaafar were fourth and sixth for Carlin, either side of the team's 2012 FR3.5 driver Will Stevens, who was out with DAMS.
Notable drivers getting their first taste of FR3.5 machinery on day two included new Formula Renault Eurocup champion Stoffel Vandoorne (18th with Arden Caterham), and Formula 2 front-runner Matheo Tuscher (21st with Pons). The latter – aged just 15 – is the youngest driver to ever get behind the wheel of one of the Renault machines.