Lewis Hamilton set the fastest time on the penultimate day of pre-season testing at the Circuit de Catalunya.
Hamilton's time of 1:20.558, set shortly before the lunch break on soft tyres, is the quickest time of the testing campaign so far.
Ferrari's Felipe Massa was 0.7s further back on the Super-soft tyres, although his day was brought to a premature halt when a wheelnut appeared to explode as he exited Turn 9. His front left wheel detached and the Brazilian came to a safe halt at Turn 10.
Returning Force India driver Adrian Sutil was third, ahead of Williams's Pastor Maldonado and Valtteri Bottas, who split driving duties on Day 3.
Esteban Gutierrez was sixth, with Mark Webber seventh and Sergio Perez in eighth.
Reigning GP2 champion Davide Valsecchi completed sixteen laps during the morning session for Lotus before his car stopped out on circuit. The Italian replaced Kimi Raikkonen, who was feeling unwell. Regular race driver Romain Grosjean returned to the circuit in time to test during the afternoon session.
French driver Jules Bianchi made his test debut for Marussia after being confirmed at the team on Friday. Bianchi finished 0.2s clear of Caterham's Giedo van der Garde, who completed the most running with 126 laps.
| Pos | Driver | Team/Car | Time | Laps |
| 1 | Lewis Hamilton | Mercedes | 1:20.558 | 116 |
| 2 | Felipe Massa | Ferrari | 1:21.266 | 94 |
| 3 | Adrian Sutil | Force India | 1:21.627 | 109 |
| 4 | Pastor Maldonado | Williams | 1:22.305 | 34 |
| 5 | Valtteri Bottas | Williams | 1:22.468 | 31 |
| 6 | Esteban Gutierrez | Sauber | 1:22.553 | 99 |
| 7 | Mark Webber | Red Bull | 1:22.658 | 58 |
| 8 | Sergio Perez | McLaren | 1:22.694 | 101 |
| 9 | Jean Eric Vergne | Toro Rosso | 1:23.223 | 114 |
| 10 | Romain Grosjean | Lotus | 1:23.380 | 45 |
| 11 | Davide Valsecchi | Lotus | 1:23.448 | 16 |
| 12 | Jules Bianchi | Marussia | 1:24.028 | 73 |
| 13 | Giedo van der Garde | Caterham | 1:24.235 | 126 |
