Mark Webber dominated both morning and afternoon practice sessions on Friday in Sepang, setting a best overall time of 1.36.876s.

McLaren drivers Lewis Hamilton and Jenson Button were hot on the Australian's heels throughout the day, with the former taking P2 in the morning and the latter claiming P2 in the afternoon. Hamilton was in P3 in the afternoon session, 0.08s ahead of Webber's Red Bull teammate Sebastian Vettel.

With the top four drivers ending the day with only 0.214s between them, fears that the RB7 would shoot off into the sunset following the integration of their KERS unit appear to be unfounded for the moment. Unless, of course, the Austrian team are hiding their true pace until Saturday's qualifying session.

Both Mercedes and Ferrari were hoping for better weekends in Malaysia than they saw in Australia, and while neither team was able to get within 1.3s of Webber's best time, Michael Schumacher and Felipe Massa finished the day within 0.001s of each other. Whatever gains the two teams might have made in the past fortnight, for the moment they appear to be closely matched on pace.

The morning session was riddled with incidents, and both Vitaly Petrov and Jerome D'Ambrosio suffered high speed suspension failures.

Petrov was the first man to be affected at speed. The Russian driver had spent much of the morning in the garage, and with roughly 30 minutes remaining of FP1 he was lapping 11 seconds off the pace. Then Petrov's tyre disintegrated and he lost control of his car under braking for Turn 9; the Renault driver was shot into the gravel and spent the remainder of the session in the garage. While the problem was originally attributed to brake failure, Renault later confirmed that the suspension was at fault.

D'Ambrosio's accident came shortly before the chequered flag, when the Virgin driver lost his front-left suspension while braking for the final corner. The piece disintegrated in a dramatic fashion, and brought an end to his day's running.

But the morning's incidents were not restricted to problems at speed. HRT driver Narain Karthikeyan was the first to stop on track; his first timed lap was cut short by an engine billowing with smoke.

Nick Heidfeld, Petrov's Renault teammate, damaged his car when his front right brake became stuck on his wheel. The German driver limped back to the pits with a damaged tyre and floor. Heidfeld's retirement was also attributed to suspension failure; for the same fault to occur on both cars is something of a concern for Renault.

The afternoon session was a calmer affair than the morning's running, and lacked a major incident of note. There were no red flags, although HRT driver Tonio Liuzzi caused a yellow flag when he stopped his car on track approximately half way through the session. Liuzzi's engine had cut out after he ran wide on Turns 7 and 8. Pastor Maldonado brought out the only other yellow flags nearly one hour into the session, when he ran wide in the pit lane and hit an advertising hoarding.

Lotus ended the day with Heikki Kovalainen at the bottom of the timesheets. The Finnish driver was only able to complete four laps as a result of a problem with the differential, while the team's running was also affected by steering problems.

As widely expected, tyre wear was more of an issue in Sepang than at any point during the Australian Grand Prix weekend. There has yet to be a return of the 'supermarbles' seen in Barcelona during winter testing, but drivers suffered a severe lack of grip off the line as a result of marbles, with many drivers running wide at Turn 8.

To check out our Sepang Friday gallery, click here.