"We'll surely get the result the car deserves next time."
With Massa sixth ahead of the other Ferrari (Fernando Alonso), Rosberg's team-mate Michael Schumacher was the next-best finisher - eighth from a start position of 14th.
Mercedes' overall performance in Shanghai finally confirmed their strong pre-season testing pace was no mistake, and the team now have another two weeks to work on the car before the Turkey Grand Prix on 8 May.
Seven-time world champion Schumacher said: "We are heading towards the first race in Europe now and will bring some upgrades to Istanbul which should help us to improve even more.
"It is good to leave Asia with a positive feeling."
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