(CNN) -- Mercedes are preparing for a "true test" in Sunday's Monaco Grand Prix after Nico Rosberg catapulted the Silver Arrows to the fastest time in practice, with teammate Lewis Hamilton a close second. The German driver, who was raised in Monte Carlo, set the pace around the city's tight and twisting streets with a leading lap of one minute 14.769 seconds on Thursday. "It was a very productive day for us," said Rosberg, who has taken pole position for Mercedes at the last two races in Bahrain and Spain but failed to translate that into podium finishes due to the team's struggles with tire degradation.
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Nico Rosberg sets the quickest time for Mercedes in practice for Monaco Grand Prix
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Mercedes boss Ross Brawn warns Sunday's race is the real test for his team
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Fernando Alonso can become first driver to win in Monaco GP for three teams
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Red Bull lament practice pace but remain confident
Monaco Grand Prix
Monaco Grand Prix
Monaco GP
Qualifying is crucial in @placeholder, where there are few overtaking opportunities, and Mercedes will be seeking to win a fourth successive pole position in Saturday's qualifying.
Spain
Alonso, winner of the last race in @placeholder, said he had come to Monte Carlo with even more motivation to be the first driver this season to triumph in successive races -- and also make a bit of history.
Monte Carlo
Alonso, winner of the last race in Spain, said he had come to @placeholder with even more motivation to be the first driver this season to triumph in successive races -- and also make a bit of history.
Monaco Grand Prix
Monaco Grand Prix
Monaco GP
"Of course we want to win the championship, but @placeholder is a special race, let's say the most important race of the championship.
Monaco Grand Prix
Monaco Grand Prix
Monaco GP
World champions Red Bull admitted they were still looking for answers after their first run around @placeholder's legendary circuit.
Monte Carlo
You will never come to @placeholder and have the perfect day.
Monaco Grand Prix
Monaco Grand Prix
Monaco GP
"It is not completely ideal but that is Friday -- or in this case Thursday," he said, referring to @placeholder traditionally having practice a day earlier than the other races, which gives teams more time to prepare for qualifying.