The duo were comfortably quickest in the opening practice session before finishing fourth and seventh in the afternoon.
Rosberg dominated the Shanghai event last year from pole position, but the German insists he is not getting carried away.
"I don't know, it's still early," said Rosberg when asked if victory was possible.
"I'm comfortable in the car and feel quite confident [in it], it's just a matter of making the most of practice and getting qualifying right and getting the set-up for the race.
"Everything needs to be perfect, otherwise it's not going to work out. The aim is to be on the podium."
The German was also cautious when making predictions for Saturday's qualifying.
"I have to wait and see what the calculations say. We are looking OK, but we encountered a few difficulties today," he added.
Hamilton, slower than Rosberg in both sessions, said the car was handling well, but also claimed it was too early to talk about victory chances.
"Not just yet, we're working on it. The car definitely doesn't feel bad," he said. "For me, I'm still finding myself a little bit uncomfortable in the car.
"We just made a change going into this session on the brakes and it made a massive difference, a positive step, so I'm hoping to make some more steps like that just to make me more comfortable in the car."
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