On pole position at the last two races, Rosberg today began his quest for a hat-trick in exemplary fashion around the confines of Monte Carlo's tight, twisty streets.
Under warm sunshine and blue skies, Formula One's jewel in the crown glittered throughout the first 90-minute practice session, occupying a Thursday slot with Friday a traditional day of rest at this circuit.
Rosberg posted a time around the 3.340-kilometre barrier-lined circuit of one minute 16.195 seconds, his time set amid a 28-lap run on the soft tyres and likely to have impressed his rivals.
Sadly for Rosberg and Mercedes, race pace has proven their Achilles heel as the German's poles in Bahrain and Spain have yielded just 10 points from finishing ninth and sixth respectively.
On Sunday, pole should bring about the much-wanted victory given the difficulties in overtaking.
As Mark Webber conceded yesterday following his win here last year, it is easy enough to "create a train" behind when tyre management is of the essence.
As for Rosberg's team-mate Lewis Hamilton, on pole in China to give Mercedes three in a row overall, the Briton had to settle for fifth-quickest, just over a quarter of a second adrift.
Sandwiched in between the duo were Ferrari's Fernando Alonso, on a high after winning last time out in his home country of Spain and aiming to become the first man here to win with three different teams.
Alonso was just 0.087secs adrift of Rosberg, followed closley by the Lotus of Romain Grosjean and Ferrari team-mate Felipe Massa.
Behind Hamilton was Monaco specialist Pastor Maldonado in a so-far pitiful Williams that has failed to glean a single point from the opening five races.
The Venezuelan, however, was eight-tenths of a second behind Rosberg, with Webber in his Red Bull in close attendance, along with McLaren duo Jenson Button and Sergio Perez.
As for reigning triple world champion and current title pace-setter Sebastian Vettel, the Red Bull star was 10th, 1.185secs off the pace, but these are very early days in the grand scheme of things.
Kimi Raikkonen, four points behind Vettel in the title standings, was also right behind the German on track as the Finn was only 11th-quickest in his Lotus.
Unusually, the Force India pair of Paul Di Resta and Adrian Sutil failed to make an impression as they were down in 12th and 13th, both hovering around 1.4secs behind Rosberg.
Beyond them there was a gap then to the likes of Sauber, Toro Rosso, Caterham and Marussia, with the latter pairing of Jules Bianchi and Max Chilton bringing up the rear.
British rookie Chilton, in particular, was slowest of all, finishing four seconds down.
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