Button thwarts Hamilton's resurgence

(Jason Lee / Reuters)

Brawn GP's Jenson Button continued to set the Formula One pace today, posting the best time in practice ahead of Sunday's Chinese Grand Prix.

The 2009 championship leader posted a time of 1 minute, 35.679 seconds at the Shanghai International Circuit, just .025 of a second ahead of Williams' Nico Rosberg, with Button's teammate Rubens Barrichello third fastest.

Brawn again emerged as the fastest team in the afternoon session, after world champion Lewis Hamilton of McLaren was quickest in the morning, showing the benefit of a new diffuser, which had interim modifications before a completed new version is unveiled for later races.

However Hamilton was only 13th fastest in the afternoon, having only improved four tenths of a second on his morning time while others made more progress.

Another team making little progress was Ferrari. Still pointless this season, Felipe Massa and Kimi Raikkonen were 12th and 14th quickest respectively in the 20-car field.

The Red Bull pair of Mark Webber and Sebastian Vettel were fourth and fifth on the timesheets, while Toyota's Jarno Trulli and Timo Glock were sixth and eighth. Kazuki Nakajima was seventh best in his Williams.

Friday's sessions were the first opportunity for teams to test the parts they had changed in the two-week break since the previous race in Malaysia, due to this year's ban on in-season testing.

Aside from the diffuser improvements and other aerodynamic changes, Ferrari has jettisoned the KERS energy-boost technology, after experiencing a failure at Malaysia. While the removal would cost the Ferraris speed off the grid and down the very long Shanghai straight, the reduced weight should make it more lithe through the corners.

By contrast, BMW's Robert Kubica has added the KERS device to his car, having forgone it in Australia and Malaysia because of its weight. He was a lowly 17th fastest in afternoon practice.