David Coulthard believes McLaren will give him a "very competitive" car to challenge for the title next season.
Coulthard is fighting for his Formula One future following news that Juan Pablo Montoya is to join McLaren from Williams in 2005.
The Scot set the fastest time - going quicker than Montoya - while testing the new McLaren MP4-19 this week.
"If MP4-19 runs as well as we think it should, it will be very competitive," he said.
McLaren became the first team to try out their 2004 car when Coulthard put the MP4-19 through its paces in Valencia, breaking the lap record in the process.
But the team said there was still a lot of work to be done to optimise performance for the season-opening Australian Grand Prix on 7 March.
Coulthard said: "Each year the new season presents a great challenge. A lot comes down to the performance of the car and we are keen to know how quickly we can develop the MP4-19.
"We all have to be patient and see what Melbourne will bring us, which seems a long time away, but it will soon be here."
McLaren have not confirmed whether Coulthard or team-mate Kimi Raikkonen will make way for Montoya, but the Scot is considered certain to lose his drive.
Coulthard, who has won 13 Grands Prix, is likely to be trying to impress potential new employers.
New rules for 2004 will impose greater restrictions placed on semi-automatic gearboxes, a move Coulthard admits will take time to get used to.
This year's McLaren was able to accelerate through the gears automatically, a practice banned for next season.
"I have always done manual down-shifts anyway, so that is not going to change for me at all," said Coulthard.
"Naturally though I have relied on the auto up-shifts during the last couple of seasons because it is the most efficient way to get your gearshifts spot on.
"So that will create the odd time where a driver will make a mistake, hit a limiter and it may give another guy the opportunity to overtake, but that is racing."