Michael Schumacher shook off his comeback rust today after setting the third fastest time in Spanish Grand Prix practice behind Red Bull's Sebastian Vettel and Mark Webber.
Vettel, on pole three times in four races this season, dominated a sunny afternoon by lapping the Circuit de Catalunya with a best time in one minute 19.965 seconds ahead of Australian Webber.
McLaren's world champions Lewis Hamilton, in 1:21.134, and Jenson Button had been first and second in an overcast morning session.
Schumacher, the sport's most successful driver who has struggled to match his young German team mate Nico Rosberg so far in his comeback season at the age of 41 and after three years out, was third in both sessions.
The second was stopped briefly when Germany's Nico Hulkenberg crashed his Williams.
Reverting to the chassis that he had used in pre-season testing, and armed with a longer wheelbase and new aerodynamic parts, Schumacher appeared to find the changes very much to his liking at a circuit that has handed him six of his 91 wins.
The seven-times champion was 0.582 behind Hamilton's first session pace and 0.792 slower than Vettel's in the second.
Rosberg, who has been on the podium in his last two races while Schumacher retired in Malaysia and laboured home 10th in China, was seventh.
Fernando Alonso, the double world champion preparing for his first home grand prix as a Ferrari driver, ended the afternoon in fourth place after setting only the eighth best time before lunch.
While Friday practice provides a morale boost, Saturday's qualifying will be crucial with the winner in Barcelona starting on pole position for nine years in a row.
Austrian Christian Klien made a return to Formula One after signing a reserve driver role with newcomers Hispania (HRT), taking Indian Karun Chandhok's place in the morning.
Klien lapped half a second faster than Brazilian Bruno Senna in the other Hispania before again handing over to Chandhok.
Britain's Paul di Resta also returned to the track for Force India, the tester replacing regular racer Adrian Sutil for the morning only and lapping quicker than the team's other driver Vitantonio Liuzzi.
Sauber's Spanish driver Pedro de la Rosa failed to complete a timed lap in the morning due to a gearbox problem but was 11th fastest in the afternoon.