Former world champion Lewis Hamilton set the fastest lap time in Friday morning's session at Barcelona's Catalunya circuit on the fourth and final day of testing before the start of the new Formula One season.
The British driver, who has switched from McLaren to Mercedes for the coming season, clocked 1min 23.282sec, to finish ahead of his erstwhile team-mate Jenson Button, who timed 1:23.633 in his McLaren.
Jean-Eric Vergne of France, in a Toro Rosso, was third in 1:24.071.
But due to the cold conditions, most of the drivers taking part were a long way short of the best performcences clocked up over the past three days.
The new season opens in Melbourne, Australia on March 17.
Fastest times in Friday's morning session:
1. Lewis Hamilton (GBR/Mercedes) 1:23.282, 2. Jenson Button (GBR/McLaren) 1:23.633, 3. Jean-Eric Vergne (FRA/Toro Rosso) 1:24.071, 4. Esteban Gutierrez (MEX/Sauber) 1:25.239, 5. Jules Bianchi (FRA/Force India) 1:25.732, 6. Giedo van der Garde (NED/Caterham) 1:27.429, 7. Felipe Massa (BRA/Ferrari) 1:27.563, 8. Mark Webber (AUS/Red Bull) 1:27.616, 9. Max Chilton (GBR/Marussia) 1:29.902, 10. Romain Grosjean (FRA/Lotus) 1:34.800