Mercedes W09 is 2017 car's 'big sister' - Hamilton

Lewis Hamilton says the Mercedes W09 feels like the 2017 car's "big sister". The four-time drivers' champion clocked the fastest lap of the first pre-season test on Thursday, after spending much of the previous three days in Barcelona being frustrated by the weather.

Hamilton stopped the clock at one minute 19.333 seconds on medium tyres - faster than the fastest time he managed on ultrasofts a year ago.

His best time was over half a second better than Stoffel Vandoorne managed on the same day using Pirelli's new hypersoft compound.

Hamilton gave up his running time on Tuesday and then saw Wednesday wiped out by the Arctic conditions at the Circuit de Catalunya, so the Brit was delighted to get behind the wheel.

"Today has been positive, I'm so happy that I could get in the car and I'm really excited that I could get some running in," he said.

"It's been the first time today that I've really been out to learn a lot more about the car and its characteristics.

???? @LewisHamilton ends the first test top of the times with 69 laps! ???? That’s a mega 129 for the day for the W09 EQ Power+!! #DrivenByEachOther pic.twitter.com/ynZwC0J0xQ — Mercedes-AMG F1 (@MercedesAMGF1) March 1, 2018

"I got to see what she's like and stretch her legs a little bit.

"Driving a new car is like trying to crack a new code: you have to figure out which different techniques you need to get the most out of it. But the W09 feels like last year's big sister.

"Out on track, the Pirelli tyres have been very hard to get working in these unusually cold conditions but they feel pretty good once they are up to temperature.

"Of course we've got things to learn and things to improve on balance-wise but overall my feeling is positive.

"I'm really looking forward to next week and to getting back in and learning more."