Pastor Maldonado puts Williams on top on third morning of F1 testing at Barcelona

The Williams driver set the time on super soft tyres with half-an-hour of the morning session remaining while on a run of three flying laps.

The Venezuelan, who is having his first day in the car this week after Bruno Senna and Valtteri Bottas completed a day each, ended up almost one second clear of the second fastest driver, Michael Schumacher.

The seven-time world champion, driving the new Mercedes W03, set his best time on soft compound Pirelli rubber only a few minutes before Maldonado went fastest.

Sauber driver Kamui Kobayashi was third fastest. He set his time with one hour of the morning remaining, like Schumacher running the soft compound but he later brought the session to a premature end moments before the chequered flag was due to fly after stopping at the exit of Turn 4 on an out-of-fuel run.

McLaren driver Jenson Button was fourth fastest in the MP4-27, lapping a second-and-a-half off Maldonado. He set his time shortly before lunch, running soft rubber.

Scuderia Toro Rosso's Jean-Eric Vergne had his first taste of test action for this week, ending up fifth fastest, two seconds off the pace, and completed 42 laps of running.

He finished ahead of Felipe Massa, who endured another busy morning of work as Ferrari attempts to get on top of its troubled machine. His programme included a number of straightline aero runs on start/finish.

Red Bull had a quiet morning, with Mark Webber completing only 26 laps after taking over from Sebastian Vettel.

Timo Glock drove the Virgin MVR-02 for the first time since last year's Brazilian Grand Prix. He focused on tyre evaluation work using each of the four available Pirelli tyres compounds. Glock also triggered a red flag when he spun, but was able to recover to the pits.

Caterham driver Vitaly Petrov ended the morning ninth fastest after suspension problems restricted his running. He ended up a quarter-of-a-second faster that Paul di Resta, whose Force India caused the red flag to be deployed very briefly when he lost part of his engine cover.

Morning times:

Pos  Driver         Team            Time               Laps
 1.  Maldonado      Williams        1m22.391s           52
 2.  Schumacher     Mercedes        1m23.384s  +0.993   54
 3.  Kobayashi      Sauber          1m23.582s  +1.191   59
 4.  Button         McLaren         1m23.918s  +1.527   39
 5.  Vergne         Toro Rosso      1m24.433s  +2.042   42
 6.  Massa          Ferrari         1m24.771s  +2.380   48
 7.  Webber         Red Bull        1m24.835s  +2.444   26
 8.  Glock          Marussia        1m26.173s  +3.782   51
 9.  Petrov         Caterham        1m26.929s  +4.538   23
10.  Di Resta       Force India     1m27.180s  +4.789   20