Robert Kubica completed 48 laps in his first pre-season test since 2011, the Williams reserve driver clocking a faster time than team-mate Sergey Sirotkin.
Kubica has not raced in Formula One since 2010, his career in the sport interrupted by life-altering injuries he suffered in a rally crash.
He had been tested for a seat at Williams and Renault, but was not considered by the French squad, while Sirotkin was preferred in the race seat for the Grove-based outfit.
The Pole is set to feature in three practice sessions this year, and impressed in frigid temperatures in Barcelona as he finished with a best time of one minute and 21.495 seconds, Sirotkin only able to manage a 1:21.822 from his 52 laps.
Ferrari got the better of Mercedes at the top of the leaderboard, as Sebastian Vettel set the benchmark in both laps and time.
The German completed 98 laps and topped the timesheets with a 1:19.673, Mercedes' Valtteri Bottas (94 laps) second three tenths behind.