Lewis Hamilton tops shortened first practice for the Singapore Grand Prix

Issues with the kerbing on the exit of Turns 3 and 14 developed during support race session, and led to an half-hour delay while the kerbs were removed before the session could get underway.

With only a two-hour gap between Friday practice sessions in Singapore, practice one was reduced to just 60 minutes to keep the timetable on schedule, although a further problem with the kerbing - this time at Turn 7 - brought the red flags out eight minutes from the end. Quick work by marshals saw the offending kerb section removed within five minutes so a little more running could take place.

When the session had initially got underway, Ferrari's Felipe Massa was the early pacesetter, sitting atop the times with a 1m52.043s lap for a long while.

It was only as twilight became darkness in the final 20 minutes that things began to hot up at the front. McLaren had completed little running in the first half of the session, but Jenson Button deposed Massa with a 1m50.952s when he did get going.

That was comfortably beaten by a 1m50.082s from Sebastian Vettel's Red Bull two minutes later, with the championship leader finding another 0.4s next time around.

Lewis Hamilton then appeared up front with 12 minutes to go, edging a tenth ahead of Vettel. The German soon fought back and delivered a lap half a second quicker than the McLaren's - but Hamilton had more speed to come as well, putting in a 1m48.599s to reclaim the top spot by 0.406s.

The second kerb problem prevented any further changes at the front, with most of the field braving the traffic jam at the pit exit but only a handful of drivers improving in the three minutes of running that followed the green light.

Vettel retained second, with team-mate Mark Webber third.

Aero work early in the session meant Fernando Alonso only had a few flying laps in his Ferrari. He took fourth, ahead of Button and Massa.

A strong session for Force India saw Adrian Sutil and Paul di Resta seventh and ninth, split by Michael Schumacher's Mercedes, with Nico Rosberg 10th in the sister silver car.

In his first appearance since Nurburgring practice in July, Narain Karthikeyan led HRT team-mate Daniel Ricciardo until the final moments, when he was pipped to 23rd. The Indian was given Tonio Liuzzi's car for this session as a warm-up for his racing return at his inaugural home grand prix next month.

In addition to the kerb issues, there was another a brief red flag interruption at the session's halfway point when Heikki Kovalainen's Lotus came to a halt with its front brakes on fire. Unlike last year, when the Finn famously had to put out a blaze on his Lotus himself in the race, Kovalainen was able to summon marshals to extinguish the fires, though he still assisted with pushing the car off the circuit.

The session's other main incident was a collision between Webber and Timo Glock. Contact was made as the Red Bull tried to pass the Virgin into the penultimate corner, smashing a chunk from Webber's front wing and leaving Glock with a puncture.

Pos Driver                Team                  Time               Laps
 1. Lewis Hamilton        McLaren-Mercedes      1m48.599s +         10
 2. Sebastian Vettel      Red Bull-Renault      1m49.005s + 0.406   15
 3. Mark Webber           Red Bull-Renault      1m50.066s + 1.467   16
 4. Fernando Alonso       Ferrari               1m50.596s + 1.997   11
 5. Jenson Button         McLaren-Mercedes      1m50.952s + 2.353   12
 6. Felipe Massa          Ferrari               1m52.043s + 3.444   14
 7. Adrian Sutil          Force India-Mercedes  1m52.251s + 3.652   13
 8. Michael Schumacher    Mercedes              1m52.416s + 3.817   12
 9. Paul di Resta         Force India-Mercedes  1m52.435s + 3.836   13
10. Nico Rosberg          Mercedes              1m52.815s + 4.216   13
11. Rubens Barrichello    Williams-Cosworth     1m52.991s + 4.392   17
12. Jaime Alguersuari     Toro Rosso-Ferrari    1m53.050s + 4.451   17
13. Pastor Maldonado      Williams-Cosworth     1m53.399s + 4.800   18
14. Sergio Perez          Sauber-Ferrari        1m53.703s + 5.104   19
15. Kamui Kobayashi       Sauber-Ferrari        1m53.749s + 5.150   12
16. Bruno Senna            Renault              1m53.765s + 5.166   17
17. Sebastien Buemi       Toro Rosso-Ferrari    1m53.785s + 5.186   16
18. Vitaly Petrov         Renault               1m54.736s + 6.137    8
19. Jarno Trulli          Lotus-Renault         1m54.821s + 6.222    9
20. Heikki Kovalainen     Lotus-Renault         1m56.198s + 7.599    8
21. Jerome D'Ambrosio     Virgin-Cosworth       1m57.798s + 9.199   13
22. Timo Glock            Virgin-Cosworth       1m58.792s + 10.193   6
23. Daniel Ricciardo      HRT-Cosworth          1m59.169s + 10.570  17
24. Narain Karthikeyan    HRT-Cosworth          1m59.214s + 10.615  18

All Timing Unofficial