On Wednesday Jenson Button will savour his first taste of a McLaren that left team-mate Lewis Hamilton smiling the day before.

On the final day of the opening pre-season Formula One test at the Ricardo Tormo circuit in Valencia, current champion Button will be on track along with two other past title-holders.

Seven-times king Michael Schumacher returns for a full-day in his Mercedes after his 90-minute return on Monday that brought an end to over three years in retirement.

Fernando Alonso, champion in 2005 and 2006, will finally get his hands on a Ferrari that finished top of the timesheets over the first two days this week with Felipe Massa at the wheel.

Button, though, will at least not be sitting in the sort of car which was met with abject horror by Hamilton a year ago when McLaren wheeled out their 2009 challenger in Barcelona.

Hamilton was relaxed after completing 108 laps, finishing third quickest in a time of one minute 12.256 seconds - 0.534secs behind Massa.

"It was great to be back in the car for the first time this year and to feel something different. It was a great first day," said Hamilton.

"It's too early to say that this is a car that can challenge, but I do feel it's a huge improvement from the beginning of 2009.

"It was a night-and-day feeling compared to then, and we're not two to three seconds behind.

"So the progress we're going to make from here into the last test and the first race, hopefully we can do as good a job as we did in 2009.

"We're hopeful to be competing. We were third (quickest), so we were not last, which is a nice feeling.

"The encouraging thing is reliability. We've had two days and not really had any problems, and that's a huge plus for us."

Hamilton and McLaren fought through the pain they experienced over the first half of last season and eventually turned the car into a race-winner again.

At least McLaren now have a solid platform on which to build ahead of the season-opening race in Bahrain in mid-March.

Yesterday was a good start but, as Hamilton conceded, there is more that needs to be done.

"I've kept a close eye on the development of this car," added Hamilton.

"I've seen the car evolve and having had input into it, I was very excited to see what parts had improved.

"Hopefully we've got rid of a lot of bugs we had in the previous car, and we got it, and it felt good.

"I got out smiling. All the problems I had in the last car, I don't have in this one.

"So for me, this was everything I could have asked for from a first day. It's gone well.

"We felt quite comfortable with what we did, but obviously there is a bit of time we need to find and a lot of areas where we can improve."

With Kamui Kobayashi behind the wheel, Sauber again surprisingly showed good pace as the Japanese driver split Massa and Hamilton.

Robert Kubica was fourth for Renault, followed by Nico Rosberg in his Mercedes, Williams' Rubens Barrichello and Sebastien Buemi for Toro Rosso.