Mark Webber topped the opening day of the final Formula One test before the opening race in Bahrain.
The Red Bull racer lapped the Barcelona track almost a second quicker than his nearest rival, Williams' Nico Hulkenberg.
All of the teams are present at the test - which ends on Sunday - except newcomers Meta Campos and US F1.
Campos has recently been bought out, and its new owners are confident of having cars built in time for Bahrain. US F1, in contrast, has asked to miss the opening races, and will be subject to an inspection by the FIA to ascertain whether it has any realistic hopes of racing.
1 Webber (Red Bull) 1m21.487s2 Hulkenberg (Williams) 1m22.407s +0.9203 Rosberg (Mercedes) 1m22.514s +1.0274 de la Rosa (Sauber) 1m23.144s +1.6575 Button (McLaren) 1m23.452s +1.9656 Liuzzi (Force India) 1m24.064s +2.5777 Alonso (Ferrari) 1m24.170s +2.6838 Petrov (Renault) 1m24.173s +2.6869 Alguersuari (Toro Rosso) 1m24.869s +3.38210 Di Grassi (Virgin) 1m27.057s +5.57011 Fauzy (Lotus) 1m28.002s +6.515