Once teammates in their karting days, the pair will be reunited next season as Mercedes teammates in Formula One.
German Rosberg, 27, has had the better of the great Michael Schumacher since they were paired together in 2010, but some sceptics point out that the seven time world champion was no longer the all-conquering driver of his ultra-successful initial career.
Rosberg's real test, they say, will be the 2008 world champion and long-time McLaren driver Hamilton.
But Rosberg scoffed at the claim he will have to 'prove' himself in 2013 alongside a genuine benchmark.
"Is Michael Schumacher not a real benchmark?" he is quoted by the Telegraph.
"Personally, I feel that Michael is still driving very well.
"But no, no, I understand where you're coming from and I'm excited by the challenge Lewis will provide."
But he might also be forgiven for worrying slightly about Hamilton's reputation for being a tumultuous presence on a team.
"That's just the perception in the media," Rosberg insisted. "I'm not worried.
He said that, although different, Schumacher also attracts a lot of attention.
"You couldn't get a much bigger spotlight," said Rosberg.
Already, however, Mercedes' 2013 drivers are disagreeing. Hamilton said recently that he does not expect the Brackley based team to win races next season.
"I expect to win next year," Rosberg insisted. "I don't know how many races but I expect to win next year. I wouldn't talk about the championship, that is not realistic at the moment, but I expect us to be winning races."