Barcelona Test, Day One: Shock pacesetter Max Chilton tops timesheets for Marussia

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Hamilton lapped Chilton twice in Sunday's race but it was the 23-year-old who topped the timesheet 48 hours later after producing a 1:26.464s lap during the closing minutes of the session.

Not only was there surprise at the Marussia driver's presence in P1 - not least from the team themselves - but the time was also over three seconds faster than he managed in qualifying last Saturday and would have put him fourth on the grid for the race.

Yes, look. It really is P1. Woohoo! pic.twitter.com/gRvWKSohVa

- Marussia F1 Team (@Marussia_F1Team) May 13, 2014

The time was, to a large extent, explained by Chilton's use of Pirelli's supersoft tyres but the Briton said he was delighted by progress nonetheless.

"Generally we've had quite a successful day and to end it in P1 is obviously a real bonus," said Chilton. "We've made steady progress throughout the day and to get the car to such a good place in terms of set-up, and then be able to see just how much we can extract from it, is a really big step from the race on Sunday to what we have achieved today."

Meanwhile, Hamilton, who now leads the Drivers' Championship after his fourth straight win at the weekend, was third fastest in his Mercedes behind Lotus reserve driver Charles Pic.

"It was okay. Just a normal test day, a bit better than the tyre test I had in Bahrain so it was a day where I could test some things," he told Sky Sports News.

Hamilton, who completed 79 laps in all, also said he found the track time valuable, having struggled with his car's balance in the Spanish GP even though he held off team-mate Nico Rosberg to win by just 0.6s.

"It is my job to be here and testing is important for the team to get through some things and also to get back into the car after last weekend when I was really uncomfortable in the car and get it comfortable again was important," he added.

Rosberg takes over on Wednesday, when in addition to Mercedes' own programme, they will also test a new exhaust designed to boost engine noise.

Kimi Raikkonen was fourth fastest for Ferrari, although it was a difficult day for the Scuderia as, first, a power unit failure and then floor damage caused by a spin at Turn 4 limited the Finn's running to just 21 laps.

The top ten was completed by Jean-Eric Vergne (Toro Rosso), Nico Hulkenberg (Force India), Felipe Massa (Williams), Jenson Button (McLaren), Kamui Kobayashi (Caterham), Sebastien Buemi (Red Bull) and Giedo van der Garde (Sauber).

Overnight rain meant damp conditions early on, with teams trying out Pirelli's intermediate tyre. Both Sauber and Toro Rosso tested exclusively for the Italian supplier before reverting to their own programmes on Wednesday.

The track dried out during the afternoon but Kobayashi was nevertheless caught out, with the Japanese driver causing "quite a lot of damage to the car" after hitting the barriers at Turn 3 in the last half-hour.

Barcelona test, Day One timesheet:
1) Max Chilton, Marussia, 1m26.434s, 60 laps
2) Charles Pic, Lotus, 1m26.661s, 70 laps
3) Lewis Hamilton, Mercedes, 1m26.674s, 79 laps,
4) Kimi Raikkonen, Ferrari, 1m26.965s, 20 laps,
5) Jean-Eric Vergne, Toro Rosso, 1m27.724s, 52 laps,
6) Nico Hulkenberg Force India, 1m27.727s, 53 laps,
7) Felipe Massa Williams, 1m27.756s, 55 laps,
8) Jenson Button McLaren, 1m28.333s, 74 laps,
9) Kamui Kobayashi Caterham, 1m30.101s, 72 laps,
10) Sebastien Buemi Red Bull, 1m31.440s, 54 laps,
11) Giedo van der Garde Sauber, 1m31.783s, 86 laps,