Mercedes impress during Formula One testing at the Circuit de Catalunya

Lewis Hamilton team-mate Nico Rosberg tops time sheets

Nico Rosberg behind the wheel for Mercedes (GETTY IMAGES)

Nico Rosberg has offered up hope that Mercedes might not be title also-rans this year after all.

A fortnight ago, at the first test in Jerez, Mercedes endured a woeful start to their pre-season campaign as Rosberg suffered an electrical fault to the new W04 that curtailed the opening day to just 14 laps.

Twenty-four hours later and Lewis Hamilton, on his debut in the car after joining Mercedes following six years in F1 with McLaren, was pitched into a tyre barrier by a rear brake failure after 15 laps.

Rosberg, Hamilton and Mercedes managed to atone over the following two days as they chalked up nearly 300 laps between them to prove the car is reliable.

Needing to show the car is also quick, Rosberg today led the way at the end of the first day of the second four-day test at the Circuit de Catalunya in Barcelona.

On the medium compound of Pirelli's range of tyres, Rosberg posted a lap time of one minute 22.616 seconds, just 0.9 seconds slower than the pole time set by Hamilton last year prior to him being dropped to the back of the grid for a fuel irregularity.

Although seven days of testing remain prior to the opening race of the season in Melbourne on March 17, and with the picture far from clear as to their rivals' overall performance, Mercedes will at least feel some satisfaction.

Behind Rosberg, Lotus' Kimi Raikkonen finished just seven thousandths of a second adrift after the Finn also finished the day on a set of medium Pirelli tyres.

On his return to the cockpit after skipping the first test to hone his fitness, Fernando Alonso clocked up a day-high 110 laps in his Ferrari, with his best time a third of a second behind Rosberg, and was narrowly ahead of Red Bull's triple world champion Sebastian Vettel.

As the last team to unveil their car today, the Williams FW35 was a competitive fifth quickest at the hands of Pastor Maldonado whose best time of his 86 laps was a 1:23.733.

Behind the Venezuelan were Toro Rosso's Daniel Ricciardo and Sergio Perez for McLaren, the Mexican 1.5secs adrift.

Force India's Paul di Resta finished in close attendance to Perez, with the remaining three drivers in Sauber's Esteban Gutierrez, Max Chilton for Marussia and Caterham's Charles Pic all considerably off the pace.

PA