Felipe Massa gave Ferrari's new Formula One car its track debut on Monday and said it felt entirely different to the one he drove to victory six times last year.
Formula One has made major changes for the coming season with new aerodynamic regulations and slick tyres brought in to boost overtaking.
New rules on weight distribution have been drawn up and the KERS system, which gives cars a limited power boost by recovering energy from the brakes, introduced.
"It really is a car which is totally different to what we were used to up to last year," the Brazilian told a news conference as the constructors' world champions became the first team to unveil their car.
"KERS and the aerodynamic changes mean the car is completely different to drive. This is just the beginning of a new cycle in Formula One and it will not be an easy experience."
Massa was runner-up last year to McLaren's 23-year-old Briton Lewis Hamilton, who won the driver's title by one point.
Massa had expected the first outing at Mugello to be tough but saw positive signs ahead of a proper test in Portimao, Portugal, later this month.
"This was the first day and we weren't looking to do 100 laps and good times given that they've changed the rules," he said. "Today there were small problems like on any first day but I'm happy with how it went.
"It will certainly be very different to drive this car...but you get more familiar and eventually it will be automatic. When changes are introduced it is always like that and at this stage we suffer, like last year with the lack of traction control.
"This is a situation where the driver is more important."
The 27-year-old had no regrets about last season and felt confident ahead of the season-opening Australian Grand Prix on March 29.
"The mood inside the team is pretty good. There have been great changes and maybe it will change some of the ways we work. I'm pretty happy with the work done by the team and I hope they'll continue to improve week after week," he said.
"During this holiday period I just put myself in a very normal frame of mind and tried to draw a lesson from last year. I'm not looking backwards, I'm always looking to the future."
Some observers have said the aerodynamic changes have made the new cars look ugly but Massa thought Ferrari's F60 was not too bad.
"I was positively impressed. I prefer to have an ugly car with very high performance levels," he said.