Mercedes continue to set the pace at Albert Park, as Tim Collings reports
Nico Rosberg maintained Mercedes' mastery of proceedings in Saturday's third and final practice session for the 2014 Formula 1® Rolex Australian Grand Prix when he outpaced nearest rival Jenson Button of McLaren by four-tenths of a second.
The 28-year-old German, tipped by many as a strong contender for victory this weekend at Albert Park, delivered a fast and tidy performance that edged him clear of team-mate and 2008 World Champion Lewis Hamilton on a humid and windy day.
Hamilton, who made a mistake when running on the softer tyres, ended up fourth-fastest behind two-time champion Fernando Alonso of Ferrari, but the overall speed of the two Mercedes men set the standard for the field.
Australia's Dan Ricciardo was fifth-best for Red Bull, but never able to threaten the front-runners.
The session began in warm and overcast conditions with rain spots confirming the likelihood of a possible downpour later in the day and a gusty wind making driving a tricky experience for everyone.
This signalled mixed news for the teams as many faced cooling issues with their new cars, but few would have welcomed a wet qualifying session at the first race of the year.
Frenchman Jean-Eric Vergne of Toro Rosso was the first man out and first to set a clocked lap time while Sebastian Vettel and Kimi Raikkonen remained in their respective garages.
All eyes soon focussed on the Mercedes men once the session settled down and Hamilton and Rosberg did not disappoint as they began clocking laps that suggested their rivalry will be at the centre of much drama this year.
Hamilton topped the first flurry of activity with a lap in 1:30.917 and an advantage of six-tenths of a second shortly before the rain intensified briefly.
When it relented, Hamilton having reported on team radio that his car was "more snappy and front-ended today", the sun returned to lift temperatures again.
This was not good news for Williams, however, as in-form Finn Valtteri Bottas nursed his car back to the garage with a serious gearbox issue that ended his participation in the one-hour session.
He joined frustrated Frenchman Romain Grosjean of Renault and Mexican Esteban Gutierrez of Sauber on the sidelines, all of them forced out of action by problems with their machines.
Between them, they had managed only a handful of laps while the Mercedes men rejoined the fray as the air temperature soared back to 30 degrees and the track temperature to 42.
This time, a mistake by Hamilton on the softer tyres gave Rosberg an advantage and his best lap of 1:29.375 lifted him clear at the top, the 2008 Melbourne winner left to rely on his earlier best of 1:30.919 on the harder tyres to retain fourth place.
Vettel, having struggled through the pre-season testing, continued to find it difficult to join the leading group, and wound up down in 12th place on 1:32.255. "The car is horrible," he told the Red Bull team. His engineer responded: "Can you explain what is horrible?" Reply: "Drivability. The car doesn't accelerate."
If that was miserable news for the champion, it was music to the ears of his rivals ahead of the season's opening qualifying session scheduled to take place later on Saturday afternoon.