Lewis Hamilton tops first practice for the Bahrain Grand Prix

In a fairly uneventful 90 minutes of running, the McLaren driver set a time of 1m33.572s in the middle of the session and remained unchallenged thereafter.

As expected, the teams were greeted with warm track temperatures - 27 degrees C and rising - but just as predictable was the surface layer of sand on the asphalt that prompted one team to dismissively say the morning's runs as nothing more than 'dust surveys'. It led to a slow start to the morning.

Nico Hulkenberg was the first driver to set a time, a 1m35.544s lap, 20 minutes in. Dicing with his Force India team-mate di Resta, who also moved to the top during this period, the German then improved that to a 1m34.859s.

Other early runners were Romain Grosjean and Sauber's Kamui Kobayashi, who like Caterham's Heikki Kovalainen before him, ran too hot into the tightening Turn 10 left-hander and ran over the sand-coloured painted run-off. There would be several more cases of this through the field.

By one third's distance Grosjean's Lotus, complete with a new front wing for this race, had moved to the top of the times with a 1m34.847s. The Frenchman looked fairly wild though as he explored the limits of the track.

Not long after that, Lotus's Kimi Raikkonen set a new benchmark, the Finn lowering the target to a 1m34.609s on the revised-back-to-its-original Sakhir layout.

Just before half distance the Red Bulls emerged from the pits for their first runs on the Pirelli medium primes and immediately Vettel went fastest with a 1m34.311s - the German now using the newer exhaust layout that Mark Webber chose to run in Shanghai.

But if his first lap was impressive, he followed it up with a much faster 1m33.877s, setting three purple sector times as he did so. His team-mate on the hand could only manage third fastest, having locked up on his early quick lap.

The two Mercedes were also out at the same time for their early runs on the prime tyres, but neither Nico Rosberg nor Michael Schumacher could match that Vettel time at this stage and went second and third quickest, while Jenson Button in the McLaren, went fourth.

Just before the hour mark world championship leader Hamilton moved to the top with a 1m33.572s - three tenths up on Vettel - as Rosberg and Button also improved to third and fourth, ahead of Schumacher.

Things settled down for a while after that as teams continued working through their programmes on the prime sets they'd hand back after the morning session was over.

During this period di Resta's KERS went intermittent and he was forced to switch it off, running wide at the final corner not long after that.

Despite the track being less dusty, to the surprise of the teams, few of them seemed keen to chase times massively.

But in the last 10 minutes of the session both the Force Indias made the surprising decision to make an early switch to the option tyre, which explained why di Resta jumped up to third late on and Hulkenberg ended up sixth.

Neither Ferrari made it into the top ten after a low profile session that ended with Fernando Alonso 13th and Felipe Massa 15th - split by Valtteri Bottas's Williams.

Pos Driver                Team                   Time              Laps
 1. Lewis Hamilton        McLaren-Mercedes       1m33.572            11
 2. Sebastian Vettel      Red Bull-Renault       1m33.877s  + 0.305  21
 3. Paul di Resta         Force India-Mercedes   1m34.150s  + 0.578  26
 4. Nico Rosberg          Mercedes               1m34.249s  + 0.677  23
 5. Jenson Button         McLaren-Mercedes       1m34.277s  + 0.705  14
 6. Nico Hulkenberg       Force India-Mercedes   1m34.344s  + 0.772  26
 7. Michael Schumacher    Mercedes               1m34.483s  + 0.911  17
 8. Mark Webber           Red Bull-Renault       1m34.552s  + 0.980  22
 9. Kimi Raikkonen        Lotus-Renault          1m34.609s  + 1.037  17
10. Romain Grosjean       Lotus-Renault          1m34.847s  + 1.275  20
11. Sergio Perez          Sauber-Ferrari         1m35.024s  + 1.452  22
12. Pastor Maldonado      Williams-Renault       1m35.268s  + 1.696  24
13. Fernando Alonso       Ferrari                1m35.436s  + 1.864  21
14. Valtteri Bottas       Williams-Renault       1m35.497s  + 1.925  24
15. Felipe Massa          Ferrari                1m35.719s  + 2.147  19
16. Kamui Kobayashi       Sauber-Ferrari         1m35.929s  + 2.357  24
17. Jean-Eric Vergne      Toro Rosso-Ferrari     1m36.195s  + 2.623  20
18. Heikki Kovalainen     Caterham-Renault       1m36.330s  + 2.758  11
19. Vitaly Petrov         Caterham-Renault       1m36.484s  + 2.912  18
20. Daniel Ricciardo      Toro Rosso-Ferrari     1m36.591s  + 3.019  20
21. Charles Pic           Marussia-Cosworth      1m37.467s  + 3.895  17
22. Timo Glock            Marussia-Cosworth      1m38.006s  + 4.434  18
23. Pedro de la Rosa      HRT-Cosworth           1m38.877s  + 5.305  19
24. Narain Karthikeyan    HRT-Cosworth           1m39.996s  + 6.424  23


All Timing Unofficial