Lewis Hamilton believes his McLaren-Mercedes team have a great deal of work still to do if they are to be competitive at the season-opening Australian Grand Prix in Melbourne on 29 March.
The reigning Formula One world champion is currently testing McLaren's new MP4-24 at the Jerez circuit in Spain.
"I haven't arrived here thinking I'm world champion, I've arrived thinking I've got a great team I need to push as hard as I can," the 24-year-old said. "We've got a lot of work to do to make sure we're ready for Australia."
McLaren are likely to go against the flow and start the season with the controversial new KERS energy recovery system. "We have less down force and the tyres have slightly different characteristics but otherwise it's all very similar," Hamilton said.
His McLaren partner, the Finnish driver Heikki Kovalainen, said: "I'm 99 per cent confident [the team will use KERS]. I think we are now hitting a stage where we can run it all day, reliably, without any problems."