McLaren's Lewis Hamilton topped the first practice session of the inaugural Korean Grand Prix weekend, as drivers used the opening 90 minutes of running to familiarise themselves with the new layout.
The track surface held up throughout the session and grip levels improved dramatically to allow Hamilton to beat the predicted lap time by over three seconds with a 1:40.887. Robert Kubica was within a tenth off that time in his Renault while Nico Rosberg was 0.265 behind in third.
Sebastian Vettel was Hamilton's closest championship rival with a time of 1:41.371 in fourth, while team-mate Jenson Button and Mark Webber were over a second off the pace. Fernando Alonso was a full three seconds adrift of the McLaren, but with the track set to improve with every lap of running and fuel levels varying, his Ferrari team will not be panicking.
The session got underway with a few tentative installation laps as the cars slid dramatically on the dusty surface. The first lap times were over two minutes and it took a full half hour before the dust started to clear and the drivers could properly commit to corners.
Jenson Button set a good benchmark time, but it soon became clear that conditions were improving lap-by-lap as a number of different drivers topped the timesheets, including the two Williams at one point. However, there were plenty of mistakes along the way, with Felipe Massa running wide on almost every lap at one point in the session and several other drivers taking to the run-off areas. Understeer was a big problem in the sweeping middle sector as drivers struggled to get their front tyres to bite into the two-week old tarmac at high speed.
Bruno Senna had the only major accident when his HRT spun off the circuit with what looked like a rear suspension failure. His session came to an end immediately but the large run-off area meant he could bring the car to a halt without making contact with the barriers.
Hamilton spent much of the mid part of the session in his garage as the times continued to tumble, making his fastest lap at the end of the 90 minutes even more impressive. However, with tyre wear rates quite high as the rubber worked hard to generate grip, his Bridgestones were considerably fresher than his competitors when he clocked his best time.
A couple of concerns with the track were immediately obvious at the end of the first session. A considerable layer of dust, the result of recent construction work, meant the pit lane was extremely slippery and several drivers missed their pit boxes during practice tyre stops. What's more the teams are concerned that any rain would make conditions significantly worse both in the pit lane and on the track where oils in the tarmac are still seeping to the surface.
The other worry is that the pit lane entrance filters off the apex of the final corner. With concrete barriers lining that section of the circuit and only one racing line, drivers on fast laps found themselves coming out of the blind bend only to be confronted with the gearbox of a car going considerably slower. There is little chance of a change before Sunday's race but it is likely to be a main talking point in the drivers' meeting on Friday afternoon.