McLaren F1 team bosses say they are delighted by the performance of new driver Juan Pablo Montoya in the build-up to the 2005 season.
Chief executive Martin Whitmarsh said: "He's exceeded our expectations in regard to his technical capability."
Montoya is also working on his fitness, losing 6kg between his first test with McLaren in December and last week.
Whitmarsh said: "He did 200 laps last week and said 'I feel fresh as a daisy - I've never been this fit before'."
The Colombian won the season-ending Brazilian GP for Williams last year before replacing Briton David Coulthard at McLaren.
"Thus far, contrary to some predictions from the outside, it's been fantastic working with him," Whitmarsh added. "It's been extremely positive on all levels.
"But it's early days yet. When we get into the heat of battle things will go wrong on both sides and we'll see what happens."
The team can run three cars in Friday practice sessions at grands prix as a result of finishing fifth overall in 2004.
"We will definitely run the third car," said team boss Ron Dennis. "It's certainly something that we will exploit to the maximum benefit of the team.
"We have two excellent development drivers in Alexander Wurz and Pedro de la Rosa. They are both very talented and both have renewed confidence in their abilities.
"At some appropriate stage, but not yet, we will decide which driver actually participates in (practice at) the initial races.
"We won't switch backwards and forwards. There will be an initial commitment, probably the first four races."