Nico Rosberg has defended Mercedes Grand Prix team-mate Michael Schumacher's performances thus far in F1 2011, arguing that his elder countryman's results in the opening three races 'do not reflect how good he is' - as the record-breaking multiple world champion reiterated that he will see out his three-year contract with the team.

Having been roundly outpaced and outscored by Rosberg during his comeback campaign in the top flight last year, Schumacher has again struggled to keep pace with his fellow German in 2011 to-date, failing to make the top ten on the starting grid in Australia, Malaysia or China and indeed languishing a full ten spots behind the sister 'Silver Arrow' in qualifying in Shanghai last time out.

That has reignited speculation that the 91-time grand prix-winner will cut short his three-year deal and hang up his helmet once more come season's end, but as he looks ahead to the upcoming Turkish Grand Prix in Istanbul, Rosberg - who delivered Mercedes a boost by leading in China before losing ground in the race's closing stages due to a fuel miscalculation on the part of the team - claims Schumacher has upped his game and suggests his critics ought to lay off awhile.

"Michael performs at a high level - he is strong," the 25-year-old told German publication Bild am Sonntag. "His current results do not reflect how good he is. To beat him, I have to get everything right - he's closer than last year.

"We had a more difficult start to 2011 than we had expected, and the first three races felt a little like a rollercoaster of emotions. We were all disappointed in Melbourne and Malaysia but, after leading the race in Shanghai, we have confirmed the potential of our car. The team did a very good job to take a step forward, and we learned a lot from the weekend.

"Hopefully we can now make a further step for Turkey and produce another positive performance. I am really looking forward to the race at Istanbul Park. Turn Eight is one of the most challenging corners of the year; it's taken at full-throttle for over eight seconds, with forces of up to 5G. If I had to create a fantasy F1 circuit, this corner would definitely be included!"

'Schumi' is similarly pumped up for Istanbul - one of the few grands prix on the F1 calendar that he has never won - and is adamant that his motivation to succeed and to return to the very front of the field still burns as brightly as it has ever done.

"Chasing for tenth place is not fun," he conceded in an interview with Bunte, "but that's why I'm fighting with Mercedes. Forty-two [years-old] is not the same as 25, [but] I will fulfil my three-year contract with Mercedes and afterwards work as a representative of the brand.

"It is always exciting when the calendar returns to Europe and the racing schedule becomes more intense. After returning from the first three races, I have enjoyed spending some time with my family in the short break, and I am now really looking forward to the action getting underway again.

"Istanbul Park is a great track and provides a good challenge for the drivers. It's anti-clockwise and has a lot of gradient changes and different corner layouts, so it's quite nice to drive. I know that the team have been working very hard to continue the progress that we made during the last race weekend in China and, with the help of some developments planned for Istanbul, I am confident that we can enjoy an equally positive weekend."