More pressure
Massa, who longs to be Brazil's first champion since the late Ayrton Senna in 1991 but needs to seize an early advantage over his teammate if the dream is not to slip away, may be feeling the pressure.
The same cannot be said of Raikkonen, who will feel a weight lifted after taking the title against the odds, having come so close in the past with McLaren.
The party-loving Finn is a driver who just wants to go racing and have fun. He shrugs off the paddock politics and has little interest in engaging with the media. Some find that hard to take.
"He is a brilliantly gifted driver, as good as anybody," team boss Frank Williams said last week. "But Kimi's weakness, which doesn't seem apparent at Ferrari, is that he doesn't seem that interested."
Raikkonen likes to keep life simple. He loves being in the car, hates most other things about the sport and does not intend to change that approach just because he has won a championship.
As last season showed, when the Finn came back from 17 points down with two races remaining to win the title by a single point from McLaren's Lewis Hamilton and Fernando Alonso, he is remarkably untroubled by stress or mind games and now can enjoy his racing even more.
The 28-year-old has vowed not to let winning the title change his lifestyle - whether it be racing snowmobiles under the name of the late F1 champion and party animal James Hunt or entering a powerboat race dressed in a gorilla suit.
He will not lose any sleep over the pecking order within the team, either.
"We drivers start the season at the same level, everybody, and we do the best that we can. We try to win races," he said after the launch of the new Ferrari in January.
"There's a point in the season where (if) the other guy is in a better position, you need to make sure that he can get all the efforts from the team and all the chances so I don't really worry about whether I am number one or number two."