World champion Michael Schumacher is cautious about his chances of making a winning start to the season at Sunday's Australian Grand Prix.
Schumacher has won the race four times in the last five years but says Ferrari's decision to race with last year's car could affect his chances.
"I might still win," said the German. "But running the old car will move us backwards a bit.
"Our chances are less because the competition have increased their game."
Schumacher begins his bid for his sixth straight world title - and eighth overall - with a modified version of last season's car.
The new F2005 machine is not expected to make its debut until the Spanish Grand Prix in May.
Schumacher has already admitted Ferrari could be taking a gamble but he believes the benefits of extra time to design and develop the definitive 2005 car will pay dividends over the full 19 races.
"It was a decision we took because we feel getting more time for the new car will make it arrive at a higher level than if we had it here," said the 36-year-old.
"As I said before, you do not win a championship just by winning the first race.
"You have to look at the whole season and find a strategy for what you want to achieve."
Schumacher won 13 Grands Prix on his way to last year's drivers' crown but this season he is anticipating a much tougher challenge from his rivals.
The rule changes which affect the cars' aerodynamics, tyres and engines could also test the German's dominance, although Schumacher has already picked out where his main threats lie.
"To me Renault and McLaren look to be the best prepared teams," he said.
"I believe they will have learned from their mistakes and from what we've seen from winter testing it looks like they have created quite a competitive package."
Meanwhile, Schumacher's team-mate Rubens Barrichello is determined to close the gap on the world champion in the second Ferrari.
The Brazilian finished as runner-up to Schumacher last season but was 34 points adrift.
"I'm sick of losing and I try to keep getting better and better," said Barrichello.
"The day that I feel Michael is unbeatable is the day I go home and stay with my family.
"The new season will be a bit more unpredictable. If that allows me to close the gap or even go in front of Michael remains to be seen."