Jackie Stewart believes Michael Schumacher holds the key to the destination of the drivers' title. Stewart reckons Schumacher will play a pivotal role in helping team-mate Eddie Irvine lift the crown in Sunday's Japanese Grand Prix at Suzuka.

Irvine leads McLaren's Mika Hakkinen by four points going into a race where he could become Ferrari's first champion in 20 years at the expense of Schumacher.

The German, who has earned around Stg£100 million trying to restore Ferrari's former glories, made a stunning return after seven races on the sidelines with a broken leg to gift Irvine victory in Malaysia earlier this month.

Schumacher seized pole position with almost a second to spare, held up Hakkinen for lap after lap and twice moved over during the race for his team-mate.

Three-time former champion Stewart was `surprised' at Schumacher's qualifying pace after been so long out, but admits there is no denying his brilliance in controlling a race.

"I thought he was a little too fast in qualifying," said Stewart, whose team will be renamed Jaguar Racing next season when Irvine joins from Ferrari.

"He went out on one lap and was faster in every segment and that seemed too good to be true.

"Maybe it was a change in the car or something, but I was surprised there was such a big gap.

"But I didn't expect anything less from Schumacher in the race. He is the best racing driver in the world and he will play a big part in Japan."

Irvine has already warned the McLarens of Hakkinen and David Coulthard not to try any `dirty tactics' in Sunday's showdown. But the Irishman is secure in the knowledge that he could have noone better to ride shotgun for him in a race that could turn into a fierce scrap for track positions.

"Michael is not only the best number one in the world, he is the best number two," said Irvine. "It's great that he will be there helping me on Sunday."

Hakkinen has to win the season's finale to be sure of retaining the title he won at the same track last year. But Stewart, who sold his three-year-old team to Ford earlier this year, believes Hakkinen and McLaren should have wrapped up the championship long ago and will only have themselves to blame if they lose.

"McLaren have got to get themselves together and Hakkinen has got to get himself together," said the 60-year-old Scottish legend.

"They should have won this championship by the beginning of August, but that's life. But they are a very experienced team and know what to do.

"But it would be wonderful if Eddie was the world champion - it would do a marvellous amount for him, though it does not really matter if you have that number one on the car for next year."

Stewart is not ruling out the prospect of his much-improved team and his in-form drivers affecting the outcome of the championship by snatching a victory at Suzuka.

Johnny Herbert won the final European race in Germany last month, with Rubens Barrichello third, while the Stewart Ford duo finished fourth and fifth respectively in Malaysia.

Herbert, in particular, has looked a different driver in recent races and has begun to get the better of Barrichello who replaces Irvine at Ferrari next season.

"I think our first win came considerably earlier than anyone should have expected," added Stewart, who won the last of his drivers' titles in 1973.

"To have a win like that boosts the morale of the team and Johnny certainly has come alive. The greatest thing about it is that he was having trouble qualifying.

"He could do really well on a Friday and Saturday morning, but on the Saturday afternoon on those 12 laps he just did not seem to get any real performance out of himself. He tightened up and it didn't work for him.

"At the beginning of the season we lost our testing. We did not get the durability testing we should have had because we were not geared up for it.

"We had to leave it to the back end of the season, but the team has come right. It is a good strong team now with a good, all-round package."