Last year, the team headed to Melbourne positive about its Formula 1 chances after some confidence-inspiring running in pre-season testing.
But problems with the tyres and reliability left it struggling to score points in the opening two races before its victory in China.
Rosberg thinks the team has had just as good a winter this time around, but believes it is better placed to capitalise on it when the season kicks off in Melbourne in a fortnight's time.
When asked by AUTOSPORT if he was as pleased with how things were going as he was last year, he said: "Unfortunately, yes!
"Because we did have a very decent end to the winter season testing last year but then it didn't go quite so well at the first two races. Quite badly actually. But I am confident we can do a bit better."
He added: "We are pleased in general. It has been a good winter. We've gone through the whole winter, but I don't want to speak about any performance level, or where I think I am or where others are.
"It is just not possible to know at the moment really. I think the way you can describe our winter is 'pleased' and that is it."
Although Rosberg says there are still items he wants to tick off on the final day of testing on Sunday, he has no complaints about the way things are going.
"I look forward to the last day and making the most of that, as testing is quite limited," he said. "We are never going to be happy that everything is done because that is nearly impossible in this limited time of testing, but it is good.
"I have got through everything that has been important for me. We are on top of all our main reliability issues now, and have really improved a lot there."
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