The German Mercedes driver's win came after team-mate Lewis Hamilton
retired early in the race with engine problems, around the same time
defending champion Sebastian Vettel of Red Bull also exited out of
contention.
The retirements meant both Rosberg and Ricciardo rocketed to the
forefront of race contention, having qualified in second and third
position.
Rosberg had built up a 14-second lead after 32 laps and even with
a pit-stop still to make on Ricciardo, extended that to over 16 seconds
by the 43rd lap.
Ultimately, Rosberg finished 24 seconds ahead of the Australian,
in a formidable title warning of the capabilities of Mercedes' W05 car
to the rest of the chasing pack field.
"Brilliant guys. What a car you gave me, what a car," an elated Rosberg bellowed over Mercedes' team radio.
Ricciardo's second-place finish meant a first time on a Formula
One podium for the 24-year-old Red Bull deputy and also the first time a
local had finished in a podium place at the Australian Grand Prix.
Meanwhile, McLaren's Magnussen remarkably became the first Danish
driver in history to claim a Formula One podium finish, all in his
debut season.
"Thanks guys, it's all a bit of a blur right now," Ricciardo said
over the radio, to which his engineer replied: "That's brilliant mate, I
think we can see your smile from here."
McLaren's Jenson Button finished fourth, while Ferrari's Fernando Alonso rounded out the top five.
Mercedes' superior preseason preparations for F1's technical
revolution paid dividends in Rosberg's huge victory margin, with
championship rival Red Bull struggling through winter testing to get to
grips with the new V6 turbocharged hybrid engines.
Those problems continued for a number of teams, as only 14 of the 22 cars finished on the Albert Park circuit.
First-lap crash, Hamilton and Vettel retirements ignite Albert Park
The race started in spectacular fashion as Caterham's Kamui
Kobayashi - on his return to Formula One - clipped Williams' Felipe
Massa on the first corner, sending both drivers sprawling into the
gravel and out of the race.
Pole-sitter Hamilton was forced to retire with an engine
complaint in just the third lap, before Vettel pulled into the pits to
retire soon after, having struggled with power problems from the first
lap.
Williams driver Valtteri Bottas also pushed too hard coming out
of turn 10, hitting the wall hard and breaking his rear rim, losing the
wheel two corners later.
Bottas's lost wheel forced the Finn down the grid and also
brought out the safety car, prompting early, strategic pit-stops from
the race leaders during the 12th lap.
Twenty laps in, Ricciardo was still trailing Rosberg by about
five seconds, before being told over the Red Bull radio he no longer
needed to conserve fuel, prompting an aggressive push from the
Australian.
McLaren's Jenson Button pitted to take on medium tyres after 32
laps, allowing the Briton the remainder of the race without stops after
using both tyre compounds.
Applause then emerged from the Williams garage when Bottas -
having lost his tyre so early in the race - temporarily moved up to
fifth place, having made use of the safety car superbly to repair the
damage to his wheel.
Having narrowed the gap between second and third to 1.1 seconds
on the 49th lap, Kevin Magnussen received orders to put the pressure on
Ricciardo, who looked to be struggling with eight laps to go.
But with the race all but Rosberg's, Ricciardo showed tremendous
poise to hold off the hyper-talented
Magnussen and secure the runner-up
spot.
A beaming Ricciardo thanked the enthusiastic crowd - which
erupted in applause when he lifted his second-place silverware - for the
"overwhelming" support.
"Just two or three weeks ago, I would bet everything I have that
we would not be standing up here," Ricciardo said on the podium.
"Full credit to the team for an unbelievable turn around. I don't understand how they did it, but they did.
"And thanks to the Aussie fans. The support has been completely overwhelming."
Race winner Rosberg praised his Mercedes team, saying the
Melbourne win will lay the foundations for a real tilt at the drivers'
and constructors' championships.
"It has been an amazing time in Melbourne. The support has been
fantastic, Daniel got more support than me, but that's normal," he said.
"It has been an amazing day. Everyone has worked so hard over the
weather and to have such an amazing [W05] Silver Arrow is unbelievable.
"The reliability was good and it's the perfect start to the season."