Rubens Barrichello admitted he was surprised that his upper midfield rivals did not make a second tire stop in Melbourne, having fallen from eighth to 10th briefly when he pitted and Tonio Liuzzi and Pedro de la Rosa did not.
The Brazilian eventually got back up to eighth for Williams by overtaking de la Rosa's Sauber and then benefiting from Mark Webber's tangle with Lewis Hamilton.
"It was a good race, but we should have finished in seventh really," Barrichello said. "We took the chance to change tires when we did and go for it. I thought everyone else would also come in, which is why I went for that route. More points for the team today is positive, though."
Prior to his stop, Barrichello had been comfortably established in eighth, as "best of the rest" behind the breakaway top four teams. He reckons that is Williams' limit for now.
"The car is good enough; we will just be picking up more points before we get podiums," he said.
Technical director Sam Michael agreed that better results are currently out of Williams' reach.
"It was good to get some more points, but we need to bring more performance to the car and to the engine," he said. "Doing both is the major part of our development program over the next few races."
Barrichello's teammate Nico Hulkenberg was taken out on the opening lap in a massive accident with Kamui Kobayashi and Sebastien Buemi.
"I was already in the corner when I was suddenly hit from behind by Kamui Kobayashi," Hulkenberg said. "It was quite a big impact. I'm not sure what caused it, but it's frustrating because I was looking forward to my first race here."