Manama: Nico Rosberg admitted on Thursday that he fears he will find it very difficult to maintain the supreme form which brought him a maiden victory in China last Sunday when he takes to the track for this weekend's Bahrain Grand Prix.

The 26-year-old German won for the first time in 111 races at Shanghai when he delivered the first triumph for Mercedes as a works team since the 1955 Italian Grand Prix.

But he said he felt a repeat was unlikely at the Sakhir circuit this week where high temperatures and entirely different conditions could count against him.

Speaking at a news conference in the media centre at the circuit, he told reporters: "This is a track I really enjoy. I have some very good memories here, but it's difficult to know where we are going to be.

"In Shanghai, we did very well, but previously we did have issues in the races, so it's possible it could be a bit more difficult here.

"I think the engineers have been making good progress. We are learning very quickly. We did a good job and got the best out of it over there, but the situation is different here with the temperatures and that might mean a bit more of a challenge."

Rosberg won by more than 20 seconds in China, after team-mate veteran compatriot and seven-times champion Michael Schumacher, 43, had been forced into early retirement from the race.

He added: "Everything came together. I was on top of my game all weekend. The car and the set-up were working quite well and it was enough to win by some margin. All in all it was a really strong weekend."

Rosberg also took his maiden pole position in Shanghai, ending world championship leader Briton Lewis Hamilton's run of two poles from the start of the year.

But Hamilton, who has looked strong and consistent this season for McLaren, said he was not worried and felt reassured by his more consistent form even if he had yet to win a race.

The 27-year-old Englishman has finished third in all three races so far to take top spot in the title race, two points ahead of his McLaren team-mate and countryman Jenson Button.

"The target every year is to have consistency and some years it doesn't go to plan," said Hamilton.

"But this year I am fortunate to be on the podium at each of the three races, so it's fantastic."

Hamilton played down the importance of leading the title race.

"It is very, very early in the season. In previous years you have seen the championship leaders swap positions so it doesn't mean much," he said.

He added that he was feeling stronger mentally this year.

"I definitely think that the last three years have added to where I am today - a lot of lessons learned and a lot of great and good experiences," he explained.

"We all have to keep our mind in a certain way. It is really a massive mental game, which is why I never gave up in getting on the right path, but I feel there or thereabouts now."