Romain Grosjean sets early pace in Jerez F1 test

The Frenchman jumped to the top in the final minutes when he became the first driver to dip below the 1m20s barrier.

His fastest time, a 1m19.796s, put him comfortably clear of Force India's Paul di Resta and Toro Rosso's Daniel Ricciardo.

Di Resta, Force India's only confirmed driver so far for the forthcoming campaign, had himself jumped to the top of the timesheets moments before Grosjean's charge.

Ricciardo as a result found himself shunted from first to third in a matter of minutes. The Australian had set the pace for much of the morning running on Pirelli's new hard compound.

Half a second down the road was Mercedes's Nico Rosberg, whose morning was cut short by an electrical issue which forced him to stop at Turn 11, his car briefly smoking at the rear.

Rosberg had been the pacesetter until that point but was unable to return, ending the morning with just 11 laps under his belt.

That was still more than McLaren's Jenson Button, who suffered his own early maladies.

The Briton stopped out on track just three laps into his programme, bringing out the first red flag. A fuel pump-related issue then kept him sidelined for the rest of the morning.

There were no such complaints for Pastor Maldonado in the 2012-spec Williams FW34, as the Venezuelan completed 52 laps - the most of any driver - and ended the morning in fifth.

On his first day of testing as a Sauber driver Nico Hulkenberg finished seventh fastest, behind Ferrari's Felipe Massa, sixth in the F138.

Mark Webber got Red Bull's third consecutive title defence off to a low-key start as he came home eighth, more than three seconds slower than Grosjean's benchmark.

2013 F1 rookies Giedo van der Garde (Caterham) and Max Chilton (Marussia) rounded out the day's runners, just ahead of Button.

The pair were separated by just 0.182s, although both trailed the pace-setting E21 by more than five seconds.

Morning times

Pos  Driver                Team          Time               Laps
 1.  Romain Grosjean       Lotus         1m19.796s           24
 2.  Paul di Resta         Force India   1m20.343s  +0.547   40
 3.  Daniel Ricciardo      Toro Rosso    1m20.401s  +0.605   37
 4.  Nico Rosberg          Mercedes      1m20.846s  +1.050   11
 5.  Pastor Maldonado      Williams      1m20.864s  +1.068   52
 6.  Felipe Massa          Ferrari       1m21.024s  +1.228   47
 7.  Nico Hulkenberg       Sauber        1m21.553s  +1.757   32
 8.  Mark Webber           Red Bull      1m22.959s  +3.163   42
 9.  Giedo van der Garde   Caterham      1m24.994s  +5.198   21
10.  Max Chilton           Marussia      1m25.176s  +5.380   21