Marussia's Max Chilton surprised the field after topping the times in the first day of this week's official Formula 1 test in Barcelona.
The Briton made the most of a late run on Pirelli's supersoft compound tyre to shoot to the top of the time sheets with an effort two tenths of a second quicker than Lotus test driver Charles Pic.
Spanish Grand Prix winner Lewis Hamilton had led the way for the majority of the session which began in tricky wet conditions at the Circuit de Catalunya. The championship leader finished the session in third having set his best time on a set of medium tyres.
The Mercedes squad are set to trial its new ‘megaphone‘ exhaust aimed to raise the W05's engine note in today's test session. The FIA has drafted in a team of sound experts to evaluate the exhaust's results.
Ferrari's Kimi Raikkonen was fourth fastest after day littered by issues. The Finn suffered an engine failure after just two laps which forced the team to replace the floor on the F14 T.
Toro Rosso's Jean-Eric Vergne was fifth quickest following a day of tyre evaluation work on behalf of Pirelli.
Vergne was just three thousandths of a second quicker than Force India's Nico Hulkenberg, who in turn was less than a tenth ahead of Williams‘ Felipe Massa.
McLaren's Jenson Button was 1.8 seconds off the pace of Chilton in eighth just ahead of the Caterham of Kamui Kobayashi.
A gearbox failure curtailed Red Bull's day in the afternoon leaving the test driver Sebastien Buemi five seconds off the pace.
Sauber, who were also working alongside Pirelli, completed the order with test driver Guido van der Garde.
Formula 1 Barcelona Test Day 1 Results
Pos | Driver | Team | Time | Gap |
1 | Max Chilton | Marussia-Ferrari | 1m26.434s | |
2 | Charles Pic | Lotus-Renault | 1m26.661s | +0.227s |
3 | Lewis Hamilton | Mercedes | 1m26.674s | +0.240s |
4 | Kimi Raikkonen | Ferrari | 1m26.965s | +0.531s |
5 | Jean-Eric Vergne | Toro Rosso-Renault | 1m27.724s | +1.290s |
6 | Nico Hulkenberg | Force India-Mercedes | 1m27.727s | +1.293s |
7 | Felipe Massa | Williams-Mercedes | 1m27.756s | +1.322s |
8 | Jenson Button | McLaren-Mercedes | 1m28.333s | +1.899s |
9 | Kamui Kobayashi | Caterham-Renault | 1m30.101s | +3.667s |
10 | Sebastien Buemi | Red Bull-Renault | 1m31.440s | +5.006s |
11 | Giedo van der Garde | Sauber-Ferrari | 1m31.783s | +5.349s |