Alonso keeps Ferrari on top at Valencia

After two days where Felipe Massa had led the way in the F10, it was the turn of Alonso to complete his first day of official action for Ferrari in front of more than 35,000 fans who had packed the grandstands.

Alonso took little time getting up to speed, getting down into the 1m11s window within the first hour, and setting his best time of the day - and of the whole test - with a 1m11.470s lap before a break at lunchtime.

More worrying for Alonso's rivals was not the time he did, but the fact it came so early into a long stint - as he completed eight further laps following that effort - showing that it wasn't simply a low fuel glory run.

Behind Alonso, the BMW Sauber C29 continued to raise eyebrows, as Pedro de la Rosa set the second fastest time on a day when he continued to outpace more high-profile opposition.

Despite early trouble when he clashed on-track with Nico Hulkenberg following a mix-up in the first minutes of the day, de la Rosa was consistently fast - although only his Hinwil team knows exactly how much fuel he was running. His best lap was 1m12.094s.

Michael Schumacher settled down to his first full day on track with Mercedes GP, having caused such a stir with his comeback performance on the first day of the test on Monday, to set the best time with a lap of 1m12.438s.

Although the W01 still does not have the definitive 2010 diffuser and front wing fitted yet, Schumacher set the third best time - albeit almost one second slower than Alonso's best.

Schumacher had to end his running with an hour of testing to go thanks to a small hydraulic problem, having completed 82 laps over the course of the day.

Team principal Ross Brawn admitted though that the team was not where it had hoped to be - with the outfit believed to need to make weight distribution tweaks to its car in time for the next test to optimise its performance on the narrower 2010 front tyres.

"It's always very difficult to judge. On full tanks yesterday (Tuesday) we didn't look too bad but we're a little bit off on pace and (there are problems with) the handling and balance of the car which we can fix for (the next test in) Jerez," he told the BBC. "We know what the problem is.

"Of course the other teams will be progressing as well so we are reasonable, not as quick as Ferrari and Lewis looked quick yesterday. So it looks like we've got a bit of work to do."

Schumacher himself too played down the team's chances for the start of the season.

"I wouldn't expect to be winning right from the beginning," he said. "It wasn't something that I was aiming for and expecting to be the case. But we need to be strong enough on development."

Jaime Alguersuari showed improved speed from the new Toro Rosso, with the team experiencing no repeat of the gearbox problems that had left Sebastien Buemi stranded in the pits for much of the opening day.

The Spaniard was fourth fastest at the end of the day, just ahead of world champion Jenson Button - who was getting his first taste of the new McLaren MP4-25.

Button spent the early part of the session with the team in the pits, perfecting his cockpit set-up and getting himself comfortable in his new surroundings, before completing a total of 82 laps. His best lap was 1m12.951s - 1.4 seconds adrift of Alonso.

Vitaly Petrov completed his first day of action in an F1 car, steadily building himself up to speed as he got used to the demands of grand prix machinery. His best lap of 1m13.097 came near the end of the day.

Although Renault still clearly has work to do to improve its R30, with a big aerodynamic update scheduled before the first race of the season, Petrov acquitted himself well.

At the bottom of the timesheets, Hulkenberg recovered from his morning clash with de la Rosa to complete 126 laps - just one less than Alonso - but his overall lap time will have left him feeling slightly disappointed.

Today's times:

Pos  Driver        Team                       Time     Laps
 1.  Alonso        Ferrari              (B)   1:11.470  127
 2.  de la Rosa    BMW Sauber-Ferrari   (B)   1:12.094   80
 3.  M.Schumacher  Mercedes GP          (B)   1:12.438   82
 4.  Alguersuari   Toro Rosso-Ferrari   (B)   1:12.576   97
 5.  Button        McLaren-Mercedes     (B)   1:12.951   82
 6.  Petrov        Renault              (B)   1:13.097   75
 7.  Hulkenberg    Williams-Cosworth    (B)   1:13.669  126

All Timing Unofficial