Andretti surprised Massa leads Raikkonen

Raikkonen appeared to have laid down a firm marker about his speed at the season-opening Australian Grand Prix, which he dominated from pole position, but since then his year has been hit by a series of disappointments.

After podiums in Malaysia and Bahrain, he retired from the Spanish Grand Prix and then could only finish eighth in Monaco after making contact with the barriers in qualifying.

And with Massa now ahead of the Finn in the points table, Andretti is well aware that the pressure is on Raikkonen to turn things around.

"I think Massa has had a leg up on Raikkonen - being at Ferrari before him, and having twice beaten Michael, let's remember," said Andretti in an interview with Autosport's Nigel Roebuck for the United States Grand Prix website.

"He knows the car, and he knows the people - he's part of the team. And I think Kimi, coming in, probably felt that.

"I don't know Kimi that well, but I always think he looks somewhat ... passive. I don't know if it's that way inside or not. Maybe he doesn't have the team rallying around him as much as you might expect.

"I'm on the outside, looking in, and this is just conjecture, but I was sure that Kimi would immediately take charge, and it doesn't seem to be the case at the moment.

"I'd imagine his character is stronger than Massa's, and I think that ultimately he might endure a high-pressure situation better. My feeling is that it will unfold that way, and it'll be interesting to see if it does."

Andretti believes that Massa currently has the best chance of his career to win the world championship this year.

"It'll be interesting to see whether Felipe can become a reliable team leader at Ferrari," he added.

"You often see drivers with a lot of talent, but without the mental strength to deal with it properly. In the past we've sometimes seen him crumble, but maybe now he's gained enough confidence in himself that that will change. A lot of that will have to do with the support he gets from the team - which I'm told is considerable.

"The kid was always quick, but wild. This is a critical point in his career - if ever he's dreamed of being world champion, he'll never have a better opportunity than now. He threw away a couple of races at the beginning of the year, but then he won the third."