Stewart is convinced the McLaren driver is ahead of the rest despite the Finn lagging behind Renault's Fernando Alonso in the championship race.

"Raikkonen is now the fastest driver in the world," said the Scot.

"At present he has already taken over the position of the dominant driver, even ahead of Schumacher and Alonso."

Raikkonen has pushed Alonso hard this season but his efforts have not been helped by reliability problems.

Evidence of his bad luck came during qualifying for the Italian Grand Prix where he set the fastest time but started from 11th after McLaren were forced to replace the engine.

"Renault should win the title but there's no doubt the car of the year will be the McLaren," added Stewart.

Michael was the best racing driver of his time but that period may have moved

Jackie Stewart

"Alonso has got a very good mind for such a young person and I don't think his car is anything like as fast as the McLaren."

Raikkonen is ahead of Schumacher in the driver standings as the German has struggled with an uncompetitive car this season.

Schumacher, a seven-times world champion, won 13 out of 18 races last season but has only claimed one triumph this year, and that was at the farcical US Grand Prix when only six cars competed.

And Stewart, who quit the sport after his third world title in 1973, believes Schumacher should have taken the chance to retire from a position of dominance.

"Michael now has to win more Grands Prix, not just one or two, he now has to regain the world championship and prove his dominance again if he's going to go down in history as the man of his time," said Stewart.

"It's always nice to go out on top and he had that opportunity.

"You are judged on what you last did against the competition of the day. And sport is cruel. Suddenly someone else can become the man.

"And even though you have won seven world championships or four like Alain Prost, it was immediately taken over by someone else.

"Michael was the best racing driver of his time but that period may have moved."