Nico Rosberg insists he is not getting complacent after proving stronger than his famous Mercedes teammate in the past two seasons.
Ever since seven time world champion Michael Schumacher returned from retirement in 2010, it has been 25-year-old Rosberg regularly setting the pace at the wheel of the Silver Arrows.
Calls for Schumacher, 42, to quit have intensified since his performance in Turkey, where after the race the German admitted he is missing the "big joy" of F1 at present.
But Rosberg has defended Schumacher, insisting he still respects the winner of an unprecedented 91 Grands Prix.
"He is and remains the most successful racing driver of all time," the German told Auto Motor und Sport.
"It is still very difficult to be faster than him and I must work hard in every session. Everything needs to fit together for me to stay ahead.
It is still very difficult to be faster than him
"I'm happy that it has worked well for me against him so far, but I also know that at the next race it may be difficult," added Rosberg.
The next race on the calendar is in Barcelona, where at the final test of the pre-season the W02 car seemed right on the pace.
But Rosberg warned: "The tests are far in the past and therefore now basically meaningless. In the last few races we have seen exactly where we stand."