Rosberg, who outpaced team-mate Lewis Hamilton for his third career Formula 1 pole, said that the harsh lesson he suffered when he fell from pole to ninth place in Bahrain meant that Mercedes would go into Sunday's race with a wary eye on tyre degradation.
"It has just been working really well all weekend, we've optimised everything," he said before adding, "After what we saw in Bahrain it is nice, but we cannot be over confident when we're thinking about the race result.
"We're surprised to be that quick, but it was a good qualifying and a good lap in the end, so I'm really, really happy with that.
"It's a good boost for the team, the front row is fantastic but of course we have to be a bit cautious after Bahrain."
Rosberg is confident that his team has made progress in terms of its tyre management, but is unsure if it will be enough to challenge for victory.
"The team has been working really hard to be even better, understanding how to get the most out of these tyres," he said.
"We were a bit behind in Bahrain, and we come here and there are issues again, this time it is more degrading of the tyre, so here catching up and making the most of the situation, we have improved.
"This morning was better so I am a little bit more confident.
"Still tomorrow is going to be a challenge."