Ahead of the sole remaining practice session, the air temperature is 18 degrees C, while the track temperature is 22 degrees. There is lots of cloud but it is bright and already there are quite a few fans in the main stands - at least the stands we are being shown.

While Lewis Hamilton set the pace in yesterday's exploratory session, it was world championship leader Mark Webber who was quickest in the afternoon as conditions improved and the drivers became more familiar with the track.

While Fernando Alonso was also up there, it was the McLaren duo which appeared the most comfortable, sparking that this might be their track after all. With tyre wear, particularly graining, a major issue here, not to mention the threat of rain, some are already looking to Jenson Button to pull off a surprise.

Following concerns raised by the drivers yesterday, a number of changes have been made, mostly at Turns 16 and 18 and the entrance to the pitlane.

Trulli leads the queue of eager beavers keen to get to work, a queue that includes Hamilton and Massa.

Mark Webber has opted to use a new engine, the last of the eight allotted to him this season. Tyre options are hard and soft.

Five minutes into the session all but Vettel have been out, Hamilton, Massa, Alonso and Button each having completed two installation laps.

Ten minutes into the session Vettel finally leaves the pits, the track still very, very dusty. This is not helped by the fact there are virtually no support races - other than a local series - consequently we cannot rely on GP2, GP3 or Formula BMW cars to clean up the track.

Fifteen minutes into the session, after several minutes of total inactivity, an engine fires up and Alguersuari heads down the pitlane. Shortly after, he is joined by Buemi, Kubica and di Grassi.

Alguersuari crosses the line at 1:45.671 to post the first time of the day. Moments later, teammate Buemi crosses the line at 46.410.

Sutil is one of the first drivers to make use of the generous runs offs this morning, the German, having run wide, goes eighth with a 52.733.

Buemi raises the benchmark with a 42.993 as Sutil improves to third with a 44.439. As Alguersuari complains of oversteer his engineer simply replies "keep pushing, keep pushing".

A 41.449 sees Hulkenberg go quickest, the German's future at Williams the subject of much speculation this weekend with 2010 GP2 champion Pastor Maldonado being linked with the seat.

At half-time, it's: Buemi, Hulkenberg, Liuzzi, Sutil, Alguersuari, Glock, Heidfeld, di Grassi, Kovalainen and Yamamoto. Other than their installation laps the big guns have yet to make an appearance.

Finally, a championship challenger emerges from the pits, Lewis Hamilton, followed by Massa, Alonso and Button.

A 40.795 sees Alonso go straight to the top of the timesheets, eclipsing Buemi by 0.554s. Massa can only manage 41.464, Hamilton ninth and Button eleventh. Elsewhere, the Red Bulls leave the pits.

Next time around, Button goes quickest with a 40.794 - one-thousandth of a second quicker than Alonso - only for the Spaniard to respond with a 39.942. Despite going off and kicking up a vast cloud of dust, Hamilton goes quickest with a 39.705.

As Alonso raises the benchmark with a 39.217, Webber goes fourth (40.695) on his first flying lap while teammate Vettel can only manage eleventh (41.896). As yesterday, traffic is very much an issue here.

On his second flying lap Webber improves to second with a 39.589 only to be demoted when Button goes quickest (38.939). Vettel improves to sixth with a 40.092, slotting in just behind Kubica who continues to worry the title battlers.

Having gone quickest in all three sectors, Hamilton reclaims the top spot with a 38.540, almost 0.4s quicker than his McLaren teammate.

No sooner has Webber improved to second (38.777) than Kubica improves once again, the Pole going second with a 38.766.

With fifteen minutes remaining and the drivers not switching their focus to qualifying, it's: Hamilton, Kubica, Webber, Button, Alonso, Schumacher, Buemi, Vettel and Massa.