KUALA LUMPUR, (Reuters) – Rain and Rubens  Barrichello will be Jenson Button’s main concerns this weekend  when the Briton returns as championship leader to the scene of  his first Formula One podium.

The Brawn GP cars were in a class of their own in the  Australian season-opener with Button leading Brazilian team  mate Barrichello across the line in the most successful debut  by a team in 55 years.

The chances are that the pair will be just as dominant in  Malaysia.

However, the race is another twilight affair with a 1700  local start and there is a risk that tropical downpours could  turn it into a lottery.

Button is one of the smoothest of drivers while  Barrichello, yearning for his first win since he was with  Ferrari in 2004, a noted rain master as well as the most  experienced driver on the starting grid.