The Renault driver won comfortably despite four safety-car periods, giving him two victories from three races.
Once he overtook pole position man Jenson Button on lap four, Alonso was in complete control, despite a series of accidents behind him.
The 24-year-old stretched out a 14-point championship lead over team-mate Giancarlo Fisichella and claimed his win was never in doubt.
“The race was a little bit crazy,” he said.
“I didn’t understand some moments, when I was maybe 20 seconds ahead and the gap disappeared after the safety cars.
“But the car was perfect - there wasn’t any risk of losing victory at any time.”
Alonso is on course to match last season’s stunning start, needing eight points at the San Marino Grand Prix in three weeks to match his 2005 total at the same stage.
He is aiming to give his rivals a case of déjà vu and move closer to retaining his title.
“I am on 28 points and so to repeat the same as last year I need to finish in the first two in Imola,” he said.
“The important thing is to be consistent, try to be on the podium and not make any mistakes.
“It doesn’t matter if it is 10, eight or four - any points are important.”
But Alonso believes this season will follow a similar pattern to last, when Renault started strongly only to be forced on to the back foot by McLaren.
The Spaniard has been the class of the field so far but Kimi Raikkonen’s second place in Melbourne showed the McLaren driver is beginning to hit top gear.
Alonso fears McLaren, who he will join in 2007, will ultimately match or even better Renault’s speed.
“I am pretty sure the little advantage we saw at the beginning of this year will disappear sooner or later.
“The only thing we have to do is to take the opportunities as we are now and to win these races.
“Then when the other teams improve and are similar to us, or quicker than us, we just have to finish the races.”
Raikkonen, Alonso’s title rival from last year, also expects a McLaren revival, claiming his championship bid is back on track after a difficult start.
“We now have a package which is level with the Renaults. We have had a good result and I think we are getting back in the championship now,” the Finn said.
“Maybe it is not ideal, but if you look at last year we are in a stronger position now than we were then and it is still only the beginning of the championship.”
Raikkonen’s enthusiasm is shared by team-mate Juan Pablo Montoya, who is preparing for the first European races with optimism despite a calamitous race in Melbourne.
The Colombian made an embarrassing mistake by spinning on his way to the grid and repeated the error behind the safety car early in the race.
He fought back into the points before bouncing across the kerbs and into retirement.
He said: “I think I could have finished on the podium. It’s a real shame as our package felt fantastic throughout the weekend. We can definitely go into the start of the European season with lots of confidence.”