Jenson Button remains the man to beat in Formula One despite Sebastian Vettel's victory at the Chinese Grand Prix, according to Nico Rosberg.

The Williams driver has predicted that no one will get close to the pace of Button's Brawn GP car at the Bahrain Grand Prix and that, unless he struggles with mechanical failure, the Briton will romp to victory.

And Rosberg, whose team have been tipped for victories this season with their new FW31 car, admits it can make for a depressing prospect.

“I guess a race win is possible for us but it's just not something we're thinking about,” said the 23-year-old German. “The problem is the only team that can win races is Brawn GP as they've got the quickest car and Jenson seems to be the quicker of the two drivers. Unless they mess up, we're left fighting for the scraps.”

After two difficult race weekends which have seen Rosberg throw away a 1st-turn lead to finish 8th in Malaysia and then trail in a lowly 15th in China, Williams are expected to move up the pack in Bahrain.

The desert circuit has been kind to Rosberg in the past. As an F1 rookie in 2006, he clocked the fastest lap and has twice finished in the points there in the last three years.

Williams' last win came courtesy of Juan Pablo Montoya in Brazil in 2004 and while victory for Rosberg in Bahrain is a tall order, he does believe he can make an impression.

“The team are long overdue a good result,” said the son of 1982 F1 world champion, Keke. “We've got a competitive car that can target the podium.”

However, Brawn are still the team to beat and warned their rivals today they are primed to take their third victory in four grands prix. Button and team-mate Rubens Barrichello finished third and fourth respectively at rain-hit Shanghai but the hot, dry conditions at the Sakhir circuit should favour them.

“As the first four races take place over a five-week period, it has been an intense and demanding start to the season,” said team boss Ross Brawn. “Australia, Malaysia and China produced some fantastic racing, and I am very pleased with how the team responded to the challenges faced.

“This was particularly the case in China where the team and the drivers did an excellent job.

“Although we were not able to challenge for the victory in the dramatic and unexpectedly wet conditions, we consolidated our championship position with two strong points-scoring results.

“We are expecting a dry weekend at Bahrain which will allow us to really put the car through its paces and assess our performance. The characteristics of the circuit should suit our car, and we do not expect any concerns from the high temperatures.”

Button is also feeling confident, particularly as the track is one of his favourites.

“It has some great, fast-flowing sections which really suit my driving style and allow you to push the car to its limits,” said the 29-year-old.

“It's a good circuit for overtaking, particularly at turn one after the long straight where you brake very hard from over 300kph in seventh gear down to first gear.

“People tend to brake surprisingly early here, so you can make up crucial ground if you are brave. Confidence under braking is the key to a quick lap.

“You have to believe in the car's performance and have full confidence you can stop effectively.”