Lewis Hamilton emerged fastest for Mercedes as Formula 1’s new 2017 specification cars broke cover for the first time at the opening pre-season test at Barcelona.

Hamilton clocked a session best of 1:21.76s, utilising the soft tyres, having taken over from new team-mate Valterri Bottas for the afternoon session.

The time was 3.2s faster than the benchmark set by Ferrari’s Sebastian Vettel on the opening day of pre-season test last year, albeit on a medium tyre.

This year’s cars are expected to lap 4-5 seconds faster than last year following the introduction of heavily revised aerodynamic regulations and wider Pirelli tyres.

Hamilton’s effort came while Mercedes tested its new radical T wing aerodynamic device.

The Brackley squad also tested a shark fin engine cover on its new W08 challenger during the day.

Mercedes logged the most mileage with 152 laps in the books split between Hamilton and Bottas, who was second fastest in the morning session and sixth overall.

Ferrari ended the day second fastest with four-time world champion Vettel just 0.113s shy of Hamilton’s pace following a late run on medium tyres.

The German managed to complete 128 laps in the SF70H throughout the session.

Felipe Massa was third fastest for Williams in the brad new FW40.

The Brazilian, who reversed his decision to retire from F1, managed to lap within 0.3s of Hamilton on the soft compound tyres.

Haas F1 enjoyed an encouraging first day with its VF17 that saw new signing Kevin Magnussen post the fourth fastest time following a late run on softs.

However, it proved to be an eventful day for Red Bull Racing when Daniel Ricciardo came to a halt on track after just four laps with a sensor and battery issue.

Once rectified the RB13 recorded 50 laps overall with the Australian fifth fastest on softs, 1.1s shy of Hamilton.

Sergio Perez (Force India) was seventh despite losing valuable track time to a exhaust issue ahead of Carlos Sainz (Toro Rosso) and Renault’s new recruit Nico Hulkenberg.

McLaren could only manage 29 laps after an oil leak hampered their opening day with the MCL32.

Fernando Alonso was able to post a string of timed laps with just over and hour remaining.

Sauber rounded out the field with Marcus Ericsson more than five seconds adrift of the pace.

The opening pre-season test will continue later today.

Result: Formula 1 Pre-Season Test Day 1, Barcelona