Formula One:Jackie Stewart reckons the fear of being "beaten up" by Michael Schumacher in this season's Formula One world championship has heaped pressure on Britain's Lewis Hamilton and Jenson Button.
Seven-time champion Schumacher will be the centre of attention on his return to the sport at next weekend's Bahrain Grand Prix at the age of 41.
The German's decision to end his three-year retirement means four world champions will be on the grid this season.
Stewart, Britain's most successful F1 driver with three titles, said: "It's fantastic for motor racing that he's come back because he is now the biggest focus of interest. Fernando Alonso driving a Ferrari is going to be tough to beat.
"You've got Jenson in there as world champion; you've got Lewis, who wants the world championship back.
"To see that occurring with Schumacher back, that's the extra edge - in my opinion - for them.
"Do they really want to be beaten up by a guy of 41 years, who's already been out of the sport?
"He's going to come back and say, 'I know how to do this, and I certainly know how to thread the needle'."
Stewart believes Schumacher's Mercedes team are already playing catch-up to their rivals, with the German manufacturers not taking over Brawn until after this season's car had been in development.
"Maybe it'll take him another year to get the car up to speed," Stewart said. "It may not be as good a car as Ferrari and McLaren are producing this year.
"Schumacher's so experienced and he's so good at co-ordinating people that I think you'll see the performance improving for him.
"I could see him not being up at the front row to begin with, but you certainly couldn't count him out."
This season sees Stewart's fellow Scot Paul di Resta make his debut as Force India's test and reserve driver.
Stewart, 70, is Scotland's last F1 world champion, his most recent title coming 37 years ago.
But he insisted his country was punching above its weight in motor sport, pointing to recent successes in IndyCar, at Le Mans and in rallying.
Dario Franchitti is currently the standard bearer for Scottish motor racing, having won two of the last three IndyCar Series.
But Stewart cannot see him trying his luck in F1.
"I think Dario would love to have driven Formula One," he said of Franchitti, who has raced for Stewart's Paul Stewart Racing team in the British Formula Three Championship.
"The problem is you get to a certain age or a certain period of your driving career where if people don't think you're going to do it, they don't offer you the drives that you would like to have.
"I think that happened with Dario."