Shanghai - Jenson Button underlined the early-season dominance of Brawn GP when he led the way in Friday's practice for the Chinese Formula One Grand Prix.

After trailing McLaren's world champion Lewis Hamilton in a slower morning session, Button clocked an unrivalled 1 minute 35.679 seconds on the 5.451-kilometres Shanghai International Circuit in the afternoon.

Williams driver Nico Rosberg had another strong training run for second place in 1:35.704 and Button's team-mate Rubens Barrichello was third in 1:35.881 minutes.

The Briton Button and Brazil's Barrichello claimed a one-two finish for the former Honda team in the season-opening Australian Grand Prix and Button also won the second race in Malaysia.

Brawn GP are favoured again for Sunday's race in Shanghai after an appeal court of the ruling motorsport body FIA on Wednesday ruled that diffusers used by them, Toyota and Williams were legal. The device improves downforce which allows faster laps.

The other teams are now likely to come up with similar diffusers to close the gap over the next weeks.

The best non-diffuser finishers on Friday were Red Bull drivers Mark Webber and Sebastian Vettel, who placed fourth and fifth, respectively, as the only drivers to break into the Brawn, Toyota and Williams force.

Hamilton had to settle for 13th in the afternoon in 1:36.941 minutes after some early glory in the morning when he led the way from Button and Barrichello in 1:37.334.

That was good news for battered McLaren which had Hamilton disqualified from the Australian race for misleading race stewards over an overtaking incident which will also be subject of a FIA hearing later this month.

The practice session came the day after former McLaren team boss Ron Dennis quit Formula One for good to lead a sports car division of the company, amid news reports he may have pulled strings in the background in the Australian affair and that his relationship with the Hamilton family had deteriorated beyond repair.

Hamilton's team-mate Heikki Kovalainen was marginally better in ninth place and the other top team of Ferrari also lagged behind again, with Felipe Massa 12th and Kimi Raikkonen 14th. Ferrari are yet to win a championship point while McLaren have one.

Button leads the way with 15 points from Barrichello (10) into the Shanghai race on Sunday. The qualifying session is on Saturday.