World champions Mercedes sent another signal of their continued dominance to the rest of the Formula One paddock, as Nico Rosberg was fastest on the first day of the second pre-season test in Barcelona on Tuesday.

The German and defending world champion Lewis Hamilton are sharing driving duties on each of the four days in the Catalan capital this week due to the W07's remarkable reliability.

Rosberg registered the second best time of testing so far in 1min 23.022sec as Mercedes finally used the quicker soft tyres, after completing nearly 700 laps on the first four days of testing last week on the medium compound.

"It was nice for me to be able to push some more and produce some stronger lap times," said Rosberg.

"That's when it's all the more enjoyable; taking the car to the limit and really pushing.

"It's been a good test, reliability has been good, the speed has been there - it's all working to plan."
Hamilton remained on the medium tyres, though, for his 90 laps after lunch to finish down in sixth fastest.

Williams also began to show their speed after an understated first week in Barcelona as Valtteri Bottas was second quickest, although his time of 1min 23.229sec was not exceptional given he was on ultrasoft tyres.

"It was a good day today. We managed to run without any major issues with the car," said Bottas.

"We have improved in the areas where we were weak last year."

McLaren-Honda enjoyed a more positive day as they recovered from the reliability problems suffered at the end of last week's test with a new engine as Fernando Alonso completed 93 laps.

The Spanish two-time world champion also recorded the third fastest time, but was 1.7 seconds back on Rosberg's best on the same soft tyres to again demonstrate the gulf between the McLaren project and Mercedes.

"After the disappointment of not being able to complete much running at the end of last week’s test, it was positive to get so many laps on the board today," said Alonso.

Kimi Raikkonen was down in fourth as Ferrari managed just 72 laps due to a gearbox blockage.

Dutch teenager Max Verstappen managed double that tally with a marathon 144 laps for Toro Rosso in seventh fastest.

Brazilian Felipe Nasr debuted the Sauber C35, with the Swiss team the last to unveil their new car for the new season.

Rookie Rio Haryanto's difficult start at Manor continued as he completed only two laps without registering a time due to an oil leak in the morning.

The Indonesian bounced back with 42 laps in the afternoon, but was still well adrift of the rest of the field on time.
Source: AFP