Lewis Hamilton maintained his superb form by setting the fastest practice time ahead of Sunday's Hungarian Grand Prix.

With temperatures nudging 30 degrees centigrade Hamilton again underlined he will be the man to beat at the Hungaroring circuit. Although only fourth-quickest in the morning session behind Felipe Massa and Kimi Raikkonen as well as McLaren team-mate Heikki Kovalainen, Hamilton set the record straight in the afternoon.

The 23-year-old, who has won the last two grands prix in Britain and Germany to lead the title race by four points from Massa and seven to Raikkonen, posted a lap of one minute 20.554 seconds. That was 0.194sec quicker than Nelson Piquet in his Renault, with the Brazilian and Hamilton second and first respectively as in the race at Hockenheim 12 days ago.

Piquet's lap, though, was a qualifying one on low fuel at the end of the 90-minute afternoon run, undoing his fine work with a spin on his very next lap.

Kovalainen was third overall, 0.206sec adrift of Hamilton, with double world champion Fernando Alonso fourth in his Renault.

Ferrari duo Raikkonen and Massa, second and first in the morning, were fifth and sixth in the afternoon, separated by 0.001sec, but almost half a second down on Hamilton. The BMW Saubers of Nick Heidfeld and Robert Kubica finished seventh and eighth, with Toyota's Jarno Trulli and Williams' Nico Rosberg rounding out the top 10, the latter a second off the pace.

David Coulthard was 13th in his Red Bull, with Jenson Button - a winner here two years ago - down in 16th for Honda, just over 1.5 sec behind fellow Briton Hamilton. Sebastian Vettel, meanwhile, endured a wretched day at the wheel of his Toro Rosso, propping up the timesheets on both occasions.

The young German completed just four laps in the morning due to a hydraulics issue the team seemingly failed to correct during the two-and-a-half-hour interval prior to the afternoon session. Vettel managed just five laps in that period before again trundling off track and onto the grass, albeit almost collecting Timo Glock as he slowed in his Toyota.