Hamilton currently trails Rosberg by 33 points with just four races remaining. The German has also won nine races to Lewis Hamilton's six.
Massa, who famously missed out to Hamilton in the 2008 title race thinks that Rosberg is the man for the championship.
"Nico has had a better year than (Lewis) Hamilton," the Williams driver told the Brazilian press.
"He has done a good job on the track, with the team and on the psychological side," Massa added. "There is no doubt that, this year, he deserves to be champion more than Hamilton."
Bahrain International Circuit - Winter testing